[EGD-6575] Rename Unicast with timeout as UnicastSync

Using Unicast with timeout is dangerous and strongly discouraged.
This change allows for more precise tracking of such cases.

[EGD-4734] Add PIN settings window

This window displays switch button for
disabling/enabling pin code for sim card.
Its also starting point for changing pin code.
Added actions for enabling and disabling
pin code for sim card.
Added method for checking if pin code is
set for sim card.

[EGD-5902] Phone Modes Windows

Windows for phone modes created.
Offline:FightMode/messages only ServiceCellularApi created.
ConnectionFrequency and DND options settings throught AppSettings.

[EGD-5741] Change cellular DataReceiverHandle refactor

All messages have been moved to separate handlers.

[EGD-5737] Merge master into experimental

Synchronize with master before merging

[EGD-5740] Change cellular message handlers

Phone modes dependent message handlig is moved to separated
handlers.

[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-5291] Fixes in Call App

Fix for Call ended window displayed to shortly
Separted the logic of two gui timers in call window.
Removed redundant main window in call app
Refactored CallWindow interface

[EGD-5158] Change access to the bus methods

The bus is now accessible only via Service object.

[EGD-5045] Change call flow handling for lock screen

Call requests on lock screen have to be handled
separately to allow only emergency and ICE numbers.

[EGD-5273] Add possibility of add new and delete APN

Functionality based on existing functions for APN.
additionally, context number management
(base on Quectel correspondence)
and saving APN to settings has been added.

Merge commit 'c7dd6b399' into stable

Merge branch 'master' into stable

[EGD-2501] Add gsm powerdown due to battery

Gsm model power state maintenance based on battery level.

[EGD-4737] Add VoLTE ON/OFF switch in Settings Network window

Add VoLTE ON/OFF switch in Settings Network window

[EGD-4920] Add API to get current operator name

Asynchronous API to get operator name,
also possibility to easy extend solution for
current operator technology and information about
operator selection mode (automatic/hand).

[EGD-4919] Add API functionality to set operator

Functionality for set operator (with name) and
set autoselect were added.

[EGD-4628] Add APN settings and URC handler for PDP context

Classes supporting APN settings on modem and telephone
configuration (synchronization) have been constructed.
Possibility of asynchronous execution
of individual actions via ServiceCellularAPI.
Added message with information about deactivation of the
PDP context (URC) that the
application / service can listen on.