Set default sound card to audio mixer

 - Update of gitlab CI to upload CS html doc
 - Update liblinphone submodule so it contain CS html doc generation

 Audio flowcontrol algorithm improved: try to eliminate silent audio buffers first, then use zero-crossing technique. This should cause sample drops to be more silent

+ add tests on forward file transfer message

Attempt to fix an issue where TURN Sender Indications are lost, possibly because of invalid source address in mblk_t

Better management of msiounit.m sound cards in mediastreamer2, It is now forbidden to instanciate several read (or write) filter at once, and will result in a ms_fatal(). In liblinphone, handle the use_file settings of the core in audio mixer and tone manager.

Now we use a new version of the yocto image with python3 and python3
needed modules included. See meta-bc!3

Update cmake scripts to force python3.
Update docker images to install python3 and required python3 modules
when it was not already done.

- Fix graphic glitches and black screen on msturbojpeg
- Memory optimization for jpeg convertion

Fixed displayed imdn sent when auto download incoming file transfer is enabled but chat message not marked as read

Add a way to reset camera configuration when the format has been changed by a third party. It will be reset when the application is active (=foreground)