[EGD-5158] Change access to the bus methods

The bus is now accessible only via Service object.

[EGD-5298] Microphone Adjust

Changed parameters for mic GSM path to get clear voice

Merge branch 'master' into stable

[EGD-5034] Change gain values to reduce echo during call

Default values of the gain for the build-in and headphones
microphone has been changed. Previously set excessive values
caused echo during call.

Signed-off-by: Lukasz Skrzypczak <lukasz.skrzypczak@mudita.com>

[EGD-5133] Fix settings bus add duplications

Changed Bus Channels vector to set to prevent
duplicates and cleaned logging.

[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-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.

Merge branch 'master' into stable

[EGD-4343] use new settings in ServiceAudio (#997)

* [EGD-4343] ServiceAudio moved to new settings

[EGD-4491] MMI call forwarding full support (#1069)

 * support for Basic Service Group and time
   parameter of call forwarding
 * fix RequestFactory, previously regex
   checking loop may have been left too early

[EGD-3510] audio codec configuration for headset microphone (#1004)

[EGD-3510] Audio stereo outputs fixed. Microphone bias handling for headset. Headset microphone gain adjusted.

[EGD-4357] Improve error handling in audio (#990)

 - error code can be now returned also during
   initialization
 - fixed crash when user requested to playback
   file that does not exist

[EGD-4215] Convert service-bluetooth to library

[EGD-4301] Bluetooth Audio profile support (#984)

 - implemented audio sink/source switching
 - reorganized / renamed sound events
 - moved SetBluetoothStreamData and AudioDevice instance to base Operation class
 - added audio profiles RecordingBluetoothHSP, RoutingBluetoothHSP
 - removed unused audio Profiles
 - removed redundant OutputPath and InputPath classes from CodecParamsMAX98090

[EGD-4214] Convert service audio to library

[EGD-4200] Message handling refactored. (#974)

[EGD-4176] Audio state notifications (#937)

[EGD-4118] Audio doxy cleanup (#856)

[EGD-4011] added BT audio device with A2DP playback (#870)

Co-authored-by: SP2FET <bartosz.cichocki@mudita.com>

[EGD-4099] BT set stream (#846)