[EGD-5472] Bluetooth worker state machine

State machine POC implemented using SML library.

[EGD-5311] Create Date&Time main window

- add DateAndTimeSettings class and
  dateAndTimeSettings global var
  (cache for storing date and time related settings),
- add DateAndTimeChangeRequest messages and proper
  methods in app::manager::Controller for sending them,
- handle DateAndTimeChangeRequest messages in ApplicationManager,
- add SettingRightItem::Text case for OptionSettings
  to provide possibility to add text
  on the right side of particular option,
- rename fields in db (settings_tab table):
  gs_time_format_12 to gs_time_format
  and
  gs_time_date_format to gs_date_format
- create only main Date&Time window.
  Sub windows will be added in separate task.

[EGD-5390] Add keypad backlight to GUI

Added demo connection to keypad light
GUI window.

[EGD-5387] Volte settings change problem solved

Volte settings made global. Merge issue regarding screen lock resolved

[EGD-5287] Add Languages window

- add LanguagesWindow,
- add GetCurrentDisplayLanguageRequest message used for
  sending request from LanguagesModel,
- add GetCurrentDisplayLanguageResponse message sent by
  ApplicationManager and handled by ApplicationSettingsNew,
- add setFocusOnElement method in ListView so current
  display language can be focused on when entering
  LanguagesWindow

Merge branch 'master' into stable

[EGD-5215] Add APNs list

Load APNs from service cellular.
Add ApnSettings model.
Connect ApnOptionWindow with ApnSettingsWindow.

[EGD-4960] registerVariableChange moved to Init section of apps

[EGD-5338] Add APN options window - gui

This is just GUI, window is not connected yet.
It will facilitate further development of APN settings,
and will be enhanced later.

[EGD-4995] Fix changing passcode windows

Some implementation of
"EGD-4995 Add changing passcode windows flow"
was removed from master by PR:
"EGD-4743 Add new/options windows to quotes".
This PR restores this implementation.

[EGD-4740] Add New/Edit APN window - Part1

Add New/Edit APN window - basic window/ model/ widget

[EGD-5288] Add Main system window

In settings add “System” window with all main menu items
(items are just menu positions not connected to actual windows)

[EDG-4743] Add new/options windows to quotes

Add windows for add/edit/delete quotes, use ListView for quote display.

[EDG-4717] Add screen for brightness control

Window for manual and automatic screen brightness control.

Merge branch 'master' into stable

[EGD-4995] Add changing passcode windows flow

Implement changing passcode windows flow

Merge branch 'master' into stable

[EGD-4580] Add BT settings middleware

Added bluetooth settings middleware to store BT status in settings.
Added middleware layer to handle new settings queries.

[EGD-4739] Add empty APN settings window

APN settings window without APN list.
Icon widget now accepts rich text.

[EGD-5166] Add query-callback synchronization mechanism

Receiver object cancels the callbacks at the end of its lifecycle.