Fixes and improvements

General

• fix default value of some settings (#2367): rtmpServerKey, rtmpServerCert, recordPath, rpiCameraExposure,. rpiCameraAWB, rpiCameraDenoise, rpiCameraMetering, rpiCameraAfMode,. rpiCameraAfRange, rpiCameraAfSpeed were not set correctly when missing in the configuration file.
• fix crash when processing H265 (#2378) (#2381)
• normalize configuration (#2399)
• rename 'external commands' into 'hooks' (#2400)

Recording

• support recording AC-3 tracks (#2376)
• support recording M-JPEG tracks (#2391)
• update recordDeleteAfter documentation (#2361) (#2362)
• automatically set 'record: yes' when not specified (#2366)
• fix race condition wen record agent is closing (#2369)

RTSP

• fix timestamp of outgoing RTSP/RTP packets in case of aggregated access units (#2389)
• fix compatibility with Annex-B encoded H264 SPS/PPS (bluenviron/gortsplib#402) (bluenviron/gortsplib#426)
• discard invalid H264 parameters (bluenviron/gortsplib#431). . (#2348)

SRT

• support AC-3 tracks in SRT and UDP; support recording AC-3 tracks (#2376)
• Support SRT encryption passphrases on configured paths (#2385)

UDP

• support AC-3 tracks in SRT and UDP; support recording AC-3 tracks (#2376)

RPI Camera

• rpi camera: add additional checks on configuration (#2368)

WebRTC

• fix ETag header name according to specification (#2396) (#2401)