move recording code from encoder to audio_rtp

It is bad design to have recording related code in the encoder. The
encoder should handle exclusively encoding related tasks.

Move recording related code to audio_rtp.

Change-Id: I4e2c59b09d40d1ae07b88cfb61865312a69c0942
Reviewed-by: Philippe Gorley <philippe.gorley@savoirfairelinux.com>
3 files changed