FS-11120 Handle invalid configs for avmd

This makes sure avmd session uses default values for global settings
if configuration parameters are invalid or missing.
Also add more printing for avmd. Avmd will now report media
bug direction READ_REPLACE/WRITE_REPLACE it has been started on,
and each frame it is processing if debug==1.
This also fixes confusing log on session stopped reported in FS-10732.