[EGD-4978] Add Bluetooth virtual audio device

Bluetooth audio device requires different handling than other
audio devices. The commit adds proxy device that does not
handle requests itself but instead sends requests too Bluetooth
service.

[EGD-5035] Fix error translation fs

Quickfix for error translation issue in new filesystem.

[EGD-4869] Add bluetooth message status to application settings

This change demonstrates how to work with Bluetooth messages
in application settings windows.
Responses to bluetooth status messages are mocked because
settings storage and message handlers in Service Bluetooth
are not ready yet.

[EGD-5010] Fix Text tests leaks

Fixed leaks in gui Text tests.

[EGD-4579] Add bluetooth settings storage

Add settings storage to bluetooth related items

[EGD-4952] Changelog update

[EGD-4952] Branch fix applied

[EGD-4952] Reverted usage of settings

[EDG-4952] Default value if does not exist in DB.

[EGD-4952] Added stetings for battery critical level

[EGD-4952] Cleanup

[EGD-4952] Moved battery level check to separate module

[EGD-4952] Fixes for rt1051

[EGD-4952] Added battery check at init and if crit level changed

[EGD-4952] Added critical level check + messages

Merge branch 'stable'

update changelog for v0.51.1

[EGD-5009] Change messy callback logic in audio module

Refactor audio module to use only one callback for communication
with audio service. This also simplifies the logic and removes
necessity to define defaults for audio values in multiple places.

[EGD-5022] Fix invalid open flags in vfscore

Opening file with O_CREAT mode on the mounted fat filesystem
should create file if doesn't exist. Currently it returns ENOENT
This path fix this issue. ff_fat create flags are fixed.

[EGD-5016] Fix vfs-littlefs failed mount init

Fix issue with memory leak during mount in littlefs core
when mount fails.