[EGD-5078] Fix Debug UART conditional enabling

Uart debug will be enabled only when redirecting logs to Uart

[EGD-4881] Add oscillator clock switching mechanisms

Osc will change automatically at the lowest CPU frequency,
which will save power

[EGD-5050] Add brownout detection

Brownout detectection realized through charger driver

[EGD-5089] linux battery bsp charging done added

[EGD-4999] fix charger pluging but no icon on Linux

[EGD-5061] Fix lack of audio during call

Audio might have not work if audio streams
were reused. This was fixed by introducing proper
cleaning procedures.

[EGD-5004] Add USB-CDC echo mechanism

Added echo mechanism to USB-CDC, update usb_stack submodule
and added a test case to test harness

[EGD-4694] Add CPU frequency shift mechanism

The CPU frequency changes automatically which saves energy

[EGD-5036] Change new filesystem

Due to vfs deprecation there is need
to remove all vfs calls from code.
This PR covers module bsp.

[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-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

[EGD-4534] Change audio data path synchronization

Refactor audio data path to fix several synchronization issues and
excessive copy operations on large memory blocks. Introduce
audio::Stream data structure to allow connecting audio source and sink
with a zero-copy capability.

Introduce system mechanisms:
 - critical section guard lock needed for stream synchronization
 - non-cacheable memory allocator to allocate memory for DMA safe
   buffers

Update the Googletest CMake template to match the capabilities of the
Catch2 template.

Signed-off-by: Marcin Smoczyński <smoczynski.marcin@gmail.com>
Signed-off-by: Hubert Chrzaniuk <hubert.chrzaniuk@mudita.com>

[EGD-4696] Several stabilization patches. (#1192)

Merge branch 'master' into stable

[EGD-4557] merge usb deinit nullptr fix (#1185)