[EGD-6554] Fix emulator to simulator

Fixed every mention of emulator to simulator - in
docs and shell scripts.

[EGD-6515] Answer/reject calls using headset

Clean up propagation of headset keys events
Clean up volume control with headset keys
Update key mappings for simulator
Use headset OK key to answer/reject calls

[EGD-5567] Add code coverage reporting

Add HTML and XML code coverage report generation with gcovr.

Cleanup unittests list - add missing googletest-gui to the unittests
list; remove dead functional tests.

Signed-off-by: Marcin Smoczyński <smoczynski.marcin@gmail.com>

[EGD-6238] Write Pure simulator guide

Added a simple Pure simulator guide to the docs.

[EGD-6188] Add PurePhone flash script

Currently dd doesn't handle sparse files properly,
so the mudita pure flashing script should be used
on the linux platform instad of the dd command.

Tools will be created in the build dir
example usage is: pureflash <image_file> <block_device>

[EGD-5989] Update quickstart article

Updated quickstart article with security-related info.

[EGD-5989] Update quickstart.md

Fixed a bit of a security risk.

[EGD-5965] Add BT-Harness API documentation

Added documentation:
* BT endpoint API
* BT-Harness tests

[EGD-6008] Create Pure flashing guide

Added small changes after trying to
boot the image on my own.

[EGD-6092] Create Pure flashing guide

Fixed some lines in the docs

[EGD-6092] Create Pure flashing guide

Ported Pure flashing guide on macOS/Win
to GitHub.

Co-authored-by: Michał Kamoń
<70628259+mkamonMdt@users.noreply.github.com>

[EGD-6092] Create Pure flashing guide

Ported Pure flashing guide macOS/Win to GitHub.

[EGD-5877] Remove flash script update flasing doc

Remove old flashEMMC script and update flash documentation

Update doc/boot_and_update.md

Co-authored-by: Wojtek Cichoń <wojtek.cichon@protonmail.com>

Update doc/running_on_phone.md

Co-authored-by: Wojtek Cichoń <wojtek.cichon@protonmail.com>

Update doc/running_on_phone.md

Co-authored-by: Wojtek Cichoń <wojtek.cichon@protonmail.com>

Update doc/running_on_phone.md

Co-authored-by: Wojtek Cichoń <wojtek.cichon@protonmail.com>

Update doc/boot_and_update.md

Co-authored-by: Wojtek Cichoń <wojtek.cichon@protonmail.com>

Update doc/running_on_phone.md

Co-authored-by: Wojtek Cichoń <wojtek.cichon@protonmail.com>

[EGD-5737] Merge master into experimental

Synchronize with master before merging

[EGD-5813] Add add to docker group step in bootstrap

Introduce one more step to bootstrap so user doesn't have
to run in manually.

[EGD-5737] Merge master into experimental

Keep experimental up to date with changes from master

[EGD-5737] Merge master into experimental

Keep experimental up to date with changes from master

[EGD-5737] Merge master into experimental

Keep experimental up to date with changes from master

[EGD-5737] Merge master into experimental

Keep experimental up to date with changes from master

[EGD-5737] Merge master into experimental

Keep experimental up to date with changes from master