[EGD-6319] Refactor cellular modem directory

- Removed not used files from old implementations.
- Renamed some classes to follow naming convention.
- Renamed methods to use consistent styling.
- Restructured code.

[EGD-6051] Receiving notifications on bt

Any notification could be heard via bt audio device while
it's connected to the pure.
If any notification is being played and bt device would disconnect,
playback will be stopped.
Disabled bluetooth low power as it was causing issues with the playback.
JIRA for the low power bug
https://appnroll.atlassian.net/browse/EGD-6681 .

[EGD-6602] Add documentation for home notifications

Documentation providers class structure diagrams for realization of
MVP pattern in context of home screen notifications.

[EGD-6676] PhoneLock handling with ServiceDesktop

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

[EGD-6652] Added minimalistic vfs README

It wasn't documented, minimal information added on how to mount
PurePhone partitions

[EGD-6675] Swiping through date/time input causes crash

Phone crashes whenever you try to set new calendar event and change its
date or time.

[EGD-6591] Remove excessive logs from USB stack

Removed log entries in conflict with charger driver BSP logs

[EGD-3109] Use more appropriate type instead of raw types

Position and Length used instead of raw ones

[EGD-3119] Do not convert InputEvent to numeric if not digit

Make sure InputEvent is a digit key before converting to numeric.

[EGD-6520] Show factory data on technical information window

Remove mocked data and read real data from settings db

[EGD-6645] Fix ContactGroups tests

Fixed Contact Groups tests.

[EGD-6673] Temporary fix cellular requesting for pin

Temporary fix for cellular pin request popup. To be fully
integrated with SimLockHandler.

[EGD-6650] Fix Thread Record test

Fix UT for using WAL in SQLite.

[EGD-6438] Loudspeaker headset fix

Fixed enabling loudspeaker during phone call with headphones plugged.

[EGD-6533] Fix switching window after editing contact

After saving edited contact, app was switched to
contact lists window instead of contact details.

[EGD-6626] Fix displaying bluetooth phone name in app settings

Reading bluetooth phone name was not implemented
on service bluetooth side.

[EGD-6641] Added Notifications to LockedPhone popup

Added NotificationsModel to LockedPhone popup window.

[EGD-6648] Fix Events Record tests

Update UT for work with SQLite WAL.

[EGD-6643] Fix Alarm Record tests

Fix UT Alarm Record to work with WAL in SQLite.

[EGD-5928] Fix loading default BT entries

Default BT entries weren't loaded at Pure start
because of unproper paths in `settings_tab`.
Adding `ServiceBluetooth` to paths fixes it.