Clean up top-level build file and build options, fix build issues on MinGW

Bluetooth: Inform privacy risk of using signed writes. ...

The Cordio stack uses a single CSRK. It can be used by a
malicious device to track the Mbed OS application if signed
writes are used.

Signed-off-by: Vincent Coubard <vincent.coubard@arm.com>

CMake: connectivity: Guard unit test directories ...

When unit tests or unit test stubs get added as CMake targets, they
becomes part of the "all" target and get compiled when building the
whole project. When building greentea tests we need to disable unit
tests and stubs to avoid unnecessary compilation and errors.

Merge pull request #14941 from hazzlim/update-tests-to-use-chrono ...

Update references to time values to use chrono

Greentea: Remove deprecated APIs and use chrono ...

References to time should do so using std::chrono. We reworked tests in
connectivity and drivers to use std::chrono and new APIs in order to
remove deprecation warnings resulting from deprecated API calls.
This required addition of  a macro for test assertions using std::chrono
values.

As host test "timing_drift_auto" expects time values represented as an
integral number of microseconds, we explicitly provide this in place
using "microseconds{TICKER_TIME}.count()" in the relevant ticker tests.
We recognise this is ugly, but thought it best to descriptively convert
from std::chrono to the host test's required representation.

Co-authored-by: Hari Limaye <hari.limaye@arm.com>

cmake: Avoid linking to gcov ...

Use the `--coverage` option instead of manually linking to gcov, as some
host platforms (like macOS, FreeBSD) don't have gcov by default and use
an llvm equivalent instead.

CMake: Limit the mbed-fakes-ble to required dependency mock

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: 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.

Merge pull request #14921 from paul-szczepanek-arm/fix-ble-default-db ...

BLE: suppress error when no path is passed in for ble security db

suppress error when no path is passed in for ble sec db

fix toggling off ble feature signing

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

BLE: Manual BLE security manager db synchronisation

Merge pull request #14820 from paul-szczepanek-arm/events-doc ...

BLE: Clarify ble event docs with crossreferences

CMake: Require TEST_SOURCES in greentea CMake file ...

Assumption that greentea test file is always named main.cpp is
incorrect. Updated mbed_greentea_add_test() macro to make TEST_SOURCES
parameter compulsory, which is used to specify greentea test
file(s). This allows tests to use C, or have a different name.
Therefore also updated all pre-existing greentea test CMake files to
explicity add main.cpp to TEST_SOURCES.

fix calls with params in docs so they are referenced correclty

add implicit call to preserve state on reset

missing cross refernces and grammar

ble security db complete sync implementation

add new BLE API call to sync security db with persisten storage

clarify ble event docs with corssreferences

put statements inside the correct feature guard blocks

Merge pull request #14747 from paul-szczepanek-arm/fix-adv-con ...

BLE: fix advertising set termination event

Merge pull request #14737 from paul-szczepanek-arm/cmake-ble-rebased ...

BLE: Add cmake unittest fakes for BLE and events

fix CORDIO not passing the conn id in param for adv stop event ...

the hci handle is different from host handle, this is how it's done in conn open event, we carry the conn id in the hdr.param

translate hci conn handle to host handle for adv stop event

translate adv set error codes and only act on successful stop

Fix process enable queue guard not being reset on failed runs

fix CORDIO not handling all adv set stop events

Merge pull request #14693 from 16L-YT/master ...

Fix compilation errors with kvstore - TDB_INTERNAL option to store BLE bonding info