Draft: RTC as core feature MVP

Requires front-end branch sat-mtl/tools/scenic/scenic!899

Current issues with RTC in Switcher's core MVP :

• Deadlocks at SIGINT
• Crash with "Can't resolve STUN server" and "Too many open files" after 7 streams
• Issues using SIP quiddity at same time because you cannot load two different versions of libnice in same process
• Subscribe does not manage audio yet, publish does
• Unsubscribe on "producer-removed" event not yet implemented
• 5 pub/sub edge-cases are hard-coded
  • do not publish thumbnail quiddity
  • do not publish preview quiddity
  • do not publish extshmsrc quiddity
  • do not publish Window quiddity (glfwin)
  • do not re-publish remote stream (causing a re-publishing loop)
• TURN username and password are hard-coded
• No support for separate rooms yet
• No authentication yet
• Bundles causes more edge-cases
  • RTC does not capture nickname from outside bundle
  • RTC instanciates one more time inside bundle second Switcher manager
  • current workaround is to prefer videotestsrc instead of videoTestInput bundle
• Cryptic crashes related to shmdata such as
  • "semop ReadLock Invalid argument"
  • "connect: Resource temporarily unavailable"
  • "semget: No such file or directory"
• urisrc quiddity produces non-interleaved audio that is not compatible with webrtcsink
• spdlog once threw this abort when testing with 2 switcher processes

  terminate called after throwing an instance of 'spdlog::spdlog_ex' what(): Failed opening file ~/.local/state/switcher/logs/switcher.log for writing: Too many open files Aborted