[EGD-5787] Fixes re fallback font docs

Fixed proper info about default fallback font.

[EGD-5787] Fix font-rendering docs

Added small fixes to the i18n article.

[EGD-5787] Added additional links to i18n article

Added additional links to i18n article
inside main README.md

[EGD-5787] Adding font-related docs to i18n article

Added missing content regarding adding special glyphs
and rendering the font inside MuditaOS

[EGD-5772] Add pause/resume API for media player

Simple version of pause / resume APIs has been added
for media player.

[EGD-5777] Refactored status bar battery indicator

Added an option to display a battery level in percentage

[EGD-5774] Fixed text char removal crash

Fixed text char and blocks removal handling and added
tests covering crashes.

[EGD-5794] Fix stack size overflow

There is not enough space in service cellular
stack which is causing debug problems.

[EGD-5028] Add batt critical level db

Battery critical level sotred in
database.

[EGD-5788] Fix json formatting in message endpoint responses

Responses had redundant anonymous objects which impeded parsing jsons.

[EGD-5697] Add helper functions for phone modes

They make it easier to write a code dependent on phone modes.

[EGD-5697] Framework for phone modes introduced

It allows to transmit phone modes information to listening services.

[EGD-4394] Add BT device name change

Added handling of BT device name changing

[EGD-4342] Remove audio profile db callback

This callback is not needed.

[EGD-5484] Add BT scan documentation

Added documentation related to BT scan operation

[EGD-5586] Clean up messages endpoint API

Introducing changes according to new messages endpoint api
proposal doc. All request have been updated, and some new were added.
Harness tests were updated too. These changes will be followed up with
pagination implementation.

[EGD-5324] Add Low Power documentation

Documentation describing the Low Power control algorithm and
synchronization with the system using dedicated sentinels and drivers.

[EGD-3756] Created generic ListItemWithCallbacks

Added generic template for ListItemWithCallbacks.
Replaced onDimensionsChange with callbacks.

[EGD-4797] Battery bar as widget

Battery bar now is present as
a separate widget in top bar.
Additionally refactored passing
battery status.

[EGD-5475] Add BT on/off documentation

Added documentation with on/off BT flow