[EGD-6657] ApplicationDesktop clean-up

This PR cleans-up `ApplicationDesktop` after recent changes in
home screen notifications handling.

[EGD-6676] PhoneLock handling with ServiceDesktop

Replaced old PhoneLock handler in ServiceDesktop with new
interactions with Application Manager PhoneLockHandler.

[EGD-5884] Added Lock Screen popup handling

Moved lock screen window to popup. Split DesktopMainWindow into
two parts (popup and regular). Added LockPhoneHandler into
ApplicationManager.

[EGD-6337] Add desktop tethering notification

This PR adds home screen tethering notification. The notifications
allows user to disconnect tethering from desktop by focusing on
the notification and pressing `KEY_ENTER`

This PR adds also home screen notifications icons in `.png` format.
Icons shall be converted to `.vpi` and used in other tasks regarding
home screen notifications.

[EGD-6456] ListView based desktop notification

This PR provides following changes in notifications:
- notifications were extracted as widget for pop-up-based
locked-screen implementation
- notifications are ListView based implemented
- the most recent notification is displayed on the top of the list

[EGD-6513] Volume control feedback

Added volume control feedback during music playback over Bluetooth.
Changed volume buttons handler logic in service audio to use actions
instead of messages.

[EGD-6527] Internationalization API unification

Single api to rule i18n
all calls to localistaion in cpp files unified
cut off ass many dependencies in i18n header as possible

[EGD-6505] Implement “On when active” Keypad light functionality

Implement “On when active” Keypad light functionality

[EGD-6486] Fix for settings not avaialble at phone startup

Fixed the comparison function of EntryPath objects.

[EGD-6494] Application Manager on action switch fix

Application Manager switch on Action no longer causes to
newly opened application main window switch but it
calls declared action handler.

[EGD-6347] Refactored phone modes handling in applications

PhoneModeObserver doesn't work properly in applications.
Applications have to handle the phone mode changes via AppMgr.
Phone mode and tethering handlers separated.

[EGD-6208] Add blocking phone mode changes during tethering

When the tethering is enabled, the phone mode shouldn't change,
now, any attempt ends with a notification

[EGD-6285] Fix system close

Add proper way of closing
system services

[EGD-4736] Change PIN windows

Implement changing SIM PIN code flow

[EGD-6209] Tethering confirmation popup added

Provided a tethering confirmation popup.
The popup shows up once a USB cable is connected to a PC.

[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-5913] Fixed language assets fallback load

Fixed language assets fallback load bug causing invalid
information display on startup.

[EGD-6121] Add offline mode in service cellular

Adds entering and leaving ito offline mode in sevice
cellular. Outgoin SMS and calls are blocked Proper popups
are shown in applications Call and Messages.

[EGD-6066] Removed Message default constructor

Forced each message to have declared type as parts of Bus logic
depends on it and previously we encountered undefined
behaviours. Added tests and messages validators.

[EGD-6101] Add low battery start prevention

Device will be shutdown after
startup if SOC will be below
shutdown level