kmsbasertpendpoint: get rtcp-fb attrs from offer

Change-Id: I99f25af47f0028eafdf21826d6d44714483a724f
BaseRtpEndpoint: add class to API

It is useful to manage common RTP features.

Change-Id: I136acd15d28a729986e6c25f3961a236c43e0e6e
sdp_utils: add sdp_utils_media_get_ssrc

Change-Id: Ib76a9daaaff70cb175133954be1b732aa3b8da81
common: format CMakeLists

Change-Id: I558a426207e823391b2fb87ac7d6eaf0265ef0fc
kmsbasertpendpoint: implement base start_transport_send

- Manage REMB

Change-Id: I57a1f32ce8f33d2900f2576cf7b099cabbb31aa6
kmsremb: add FIXME

Change-Id: I308ee463fff7687d85cd076ed8ce14e239c775b6
kmsbasertpendpoint: create always the RtpSession when update_sdp_media

Change-Id: If3712c7b8fe9c867352ba1b4b88c78b2ae97cb2c