docs: Update docs with firmware encryption feature ...

Update documentation with optional firmware encryption feature.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Change-Id: I26691b18e1ee52a73090954260f26f2865c4e05a

change-log: Add fconf entry ...

Change-Id: I6686f172d0c24f6c457a39cdf4debcbf05475540
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>

Add support for documentation build as a target in Makefile ...

Command to build HTML-formatted pages from docs:
make doc

Change-Id: I4103c804b3564fe67d8fc5a3373679daabf3f2e9
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>

docs: Creating a Change Log Template File ...

Creating a Change Log Template for ALL to update with relevant
new features, changes, fixes and known issues for each upcoming
release of Trusted Firmware-A.

The contents of this file should be added to the collective change log
at the time of release code freeze.

Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: Idfbdcef0d40b10312dc88b6e1cbe31856fda887e