rtp_engine: Add support for transporting signed linear at 12kHz, 24kHz, 32kHz, 44kHz, 48kHz, 96kHz, and 192kHz over RTP.

This change adds mappings in the RTP engine layer for the remaining signed linear formats.

ASTERISK-24274 #close
Reported by: Frankie Chin

Review: https://reviewboard.asterisk.org/r/4093/


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@428708 f38db490-d61c-443f-a65b-d21fe96a405b