* Add control of playout delay
Add config to enable playout delay. The delay will be limited by
[min,max] in the config option and calculated by upstream & downstream
RTT.
* check protocol version to enable playout delay
* Move config to room, limit playout-delay update interval, solve comments
* Remove adaptive playout-delay
* Remove unused config
* Decode chains
* clean up
* clean up
* decode targets only on publisher side
* comment out supported codecs
* fix test compile
* fix another test compile
* Adding TODO notes
* chainID -> chainIdx
* do not need to check for switch up point when using chains, as long as chain integrity is good, can switch
* more comments
* address comments
