Converting between different codec representations is confusing. This
codec mapping provides a consolidated overview of all our codec
representations, and how they match up.
In particular, it adds the SDP codec representation repertoire,
preparing the use of full SDP on the MNCC interface.
Related: SYS#5066
Change-Id: Iaa307be6a8487aa8d4ba7cd59d5c5ef04818a744