VT: Add TMMBN feature on RTP Tx side

StagefrightRecorder adjusts encoding rate and sends TMMBN as requested bitrate.

1. Add TMMBN packetizing function on ARTPWriter.
2. StagefrightRecorder holds opponent's SSRC ID that is used for TMMBN.
3. MediaRecorder can set parameter on RECORDING state if format is for RTP.

Merged-in: I768649c02e50fd5fab2ecb53c3743915662c100a
Change-Id: I768649c02e50fd5fab2ecb53c3743915662c100a
Signed-off-by: Kim Sungyeon <sy85.kim@samsung.com>