There was issue with certain endpoints that would lead to dropping
nearly every other RTP packet from the callee.

The scenario is as follows: the caller (bridged through FreeSWITCH)
offers codecs A and B with payload types X and Y, respectively.
The callee answers with codec B and payload type X.

The fix is to use the sender's expected payload type when checking
against the received RTP packet, rather than the receiver's.

FS-9653 #resolve freeswitch-meta-all-dbg should not depend on non-existant freeswitch-meta-lang-dbg %backport=1.6

FS-9642 #resolve do not limit time for real time threads with systemd. this causes systemd to randomly restart FreeSWITCH without notice as to why. %backport=1.6

FS-9648 #resolve [Conference avatar image gets stuck enabled when it uses the same image as video mute]

FS-9612 #resolve [RTCP-MUX wrongly enabled in cases where answer contains rtcp but offer didn't / remote addr not obtained in UDPTL mode] %backport=1.6

FS-9601: mod_opus:  make adjustable bitrate mutually exclusive with FEC enforcing on the decreasing trend,
add step calculation for bitrate adjustment, fix bug on context settings

FS-8644: OPUS_SET_BITRATE(), codec control and estimators for packet loss and RTT (with Kalman filters) to detect a slow or congested link.
Feature enabled with "adjust-bitrate" in opus.conf.xml - it's a feedback loop with incoming RTCP.

Merge pull request #969 in FS/freeswitch from ~DRAGOS_OANCEA/freeswitch-dragos:fix_config_rtpip to master

* commit '3d2f3c96':
  FS-9548: return with error on wrong rtp ip given from config

* commit 'c70f06aa':
  FS-9553 #resolve [Refactor video-on-hold]