CMake: Move ble fakes into FEATURE_BLE double dir ...

Previously ble fakes as part of UNITTESTS/fakes, this PR moves
ble fakes to FEATURE_BLE double directory to make ble stubs
to be self-contained.

CMake: fakes ble: Remove trailing whitespace

CMake: Create mbed-headers-ble library ...

Previously ble headers are part of mbed-headers-connectivity, this PR
moves ble headers into new mbed-headers-ble to make ble stubs to be
more self-contained and improves the composition of the library.

CMake: Add mbed-headers-nanostack-libservice library ...

Previously all nanostack libservice headers part of
mbed-headers-connectivity. This PR moves all the nanostack
libservice headers into newly added mbed-headers-nanostack-libraries.
This makes the nanostack libservice stubs more self-contained and
improves the composition of the library.

CMake: Move nanostack libservice stubs to the connectivity/libraries dir ...

Move the connectivity nanostack-libservice stubs into the connectivity/libraries
directory where the nanostack libservice component present as nanostack
libservice source copied from the external repo. So we can avoid duplicating
the mbed-os source tree in a central UNITTESTS folder.

CMake: Move mbedtls stub headers to the mbedtls doubles dir ...

Previously all the mbedtls stubs headers under mbed-stubs-headers,
so this PR move all mbedtls stubs headers under
mbedtls/tests/UNITTESTS/double directory and update CMake to include
stubs headers into mbed-stubs-mbedtls library to make mbedtls stubs
to be self-contained.

CMake: Update netsocket, lorawan unittest to use mbed-stubs-mbedtls ...

Update netsocket and lorawan unit tests to link with a mbed-stubs-mbedtls
library that it depends on instead of link with mbed-stubs
which is a group of stubs libraries.

CMake: Move mbedtls stubs to the mbedtls dir ...

Move the connectivity mbedtls stubs into the connectivity/mbedtls
component directory. So we can avoid duplicating the mbed-os source
tree in a central UNITTESTS folder.

Merge pull request #14824 from paul-szczepanek-arm/persistence-fix ...

BLE: Manual BLE security manager db synchronisation

CMake: Move events fakes into events double dir ...

Previously events fakes as part of UNITTESTS/fakes, this PR moves
events fakes to events double directory to make events stubs
to be self-contained.

Remove trailing space

CMake: Move events stub headers to the events/tests/UNITTESTS/double dir ...

Move events stubs headers to the mbed-os/events/tests/UNITTESTS/double
directory and update double CMake to include stub headers

CMake: unit-tests: Move mbed-headers-events to the events directory ...

Move the header-only mbed-headers-events library the unit test stubs
depend on into the events component directory. This makes the events
stubs more self-contained and improves the composition of the library.

CMake: Move events stubs sources to the mbed-os/events directory ...

Move the events stub into the events component directory.
so we can avoid duplicating the mbed-os source tree in a central
UNITTESTS folder.

CMake: Remove mbed-stubs-rtos-headers library ...

- Previous changes moved all rtos stubs headers into mbed-stubs-rtos-headers
lib, but the decision to keep all stubs headers under the respective
component stubs library so moved all stubs rtos headers under
mbed-stubs-rtos and updated it depend component CMake
- Remove unnecessary add_definition call for UNITTEST as any of the stubs library
added from UNITTEST/CMakeLists.txt is not required this macro

Merge pull request #14873 from ARMmbed/move_connectivity_netsocket_stubs ...

Move connectivity netsocket stubs

Merge pull request #14773 from rwalton-arm/move_platform_stub ...

Move mbed-stubs-platform to the platform directory

Merge pull request #14884 from LDong-Arm/rm_UNITTEST_macro ...

Remove the `UNITTEST` macro from production code

Merge pull request #14835 from ARMmbed/move_stubs_cellular_headers ...

Move stubs cellular headers

CMake: Move netsocket stub headers to the netsocket doubles dir ...

Previously all the netsocket stubs headers under mbed-stubs-headers,
so this PR move all netsocket stubs headers under
netsocket/tests/UNITTESTS/double directory and update CMake to include
stubs headers into mbed-stubs-netsocket library to make netsocket stubs
to be self-contained.

CMake: Add mbed-headers-netsocket headers library ...

- Previously, all netsocket headers made as a part of the
mbed-headers-connectivity library. To make it easier to separate all
the netsocket headers into the separate mbed-headers-netsocket library
and keep them, as part of netsocket stubs CMake. This makes the
netsocket stubs more self-contained and improves the composition of the library.
- Update cellular, netsocket unit tests to link only with a mbed-headers-netsocket
library that it depends on instead of link with mbed-headers
which is a group of headers libraries.

CMake: Move netsocket stubs to the netsocket dir ...

Move the connectivity netsocket stubs into the connectivity/netsocket
component directory. So we can avoid duplicating the mbed-os source
tree in a central UNITTESTS folder.

Merge pull request #14842 from ARMmbed/move_connectivity_lora_stubs ...

Move connectivity lora stubs

Unit tests: Update <mstd_type_traits> stub ...

The stub version of <mstd_type_traits> is mostly identical to the
production file of the same name, except the former lags behind
and doesn't contain the recent "is_constant_evaluated" feature.
It's safe to update the stub file, because "is_constant_evaluated"
only checks generic GCC and Clang versions that also apply to
compilers on PCs.

This enables MbedCRC.h to include <mstd_type_traits> without
distinguishing between Mbed applications and unit tests.

Unit tests: Remove `#ifndef UNITTEST` from the mbed_assert.h stub ...

The stub version of mbed_assert.h is never used outside unit tests,
so the check on `UNITTEST` is redundant.

CMake: unit-tests: Split platform headers out of mbed-stubs-headers ...

We have a central collection of "stub headers", which makes reasoning
about dependencies rather difficult, as it forces every stub library to
depend on all available stub headers. The standard approach would be for
each stub library to expose its public headers, and its dependents to
explicitly specify a dependency on the stub library containing the
headers it needs. This is a more modular design than creating a
header-only monolith library. Move the platform stub headers from this
central library into the mbed-stubs-platform library to increase
modularity.

mbed-stubs-connectivity now depends on the mbed-stubs-platform because
it requires some headers which were moved to mbed-stubs-platform.

CMake: unit-tests: Move mbed-headers-platform to platform directory ...

Move the header-only mbed-headers-platform library the unit test stubs
depend on into the platform component directory. This makes the platform
stubs more self contained and improves composition of the library.

CMake: Move platform stubs to the mbed-os/platform directory ...

Move the platform stub library into the platform component directory.
This change is so we can avoid duplicating the mbed-os source tree in a
central UNITTESTS folder.

Unit tests: Remove mbed-headers-storage

Unit tests: Create mbed-headers-kvstore ...

Create a CMake target mbed-headers-kvstore to separate KVStore headers
from the generic mbed-headers-storage. Update tests to use it.