New minor features
- Metrics: new metrics system that provides more data (#492)
- API: add "state" field to RTSP sessions and RTMP connections
- API: add RTSPS endpoints to list and kick RTSPS sessions
Fixes and improvements
- General: fix crash that happens when sourceOnDemand is true and a source times out
- HLS: fix freeze when sourceOnDemand is yes and multiple sources are requested at the same time (#493)
- API: make sure that entities are deleted immediately after a kick request