link collection of useful sources

AirPlay2

• https://htmlpreview.github.io/?https://github.com/philippe44/RAOP-Player/blob/master/doc/auth_protocol.html
• https://openairplay.github.io/airplay-spec/known_implementations.html
• https://github.com/openairplay/AirPlayAuth
• https://ioncannon.net/projects/ap4j-player-java-airplay-player/
• https://github.com/espes/Slave-in-the-Magic-Mirror
• https://en.wikipedia.org/wiki/AirPlay#AirPlay_Mirroring

SRP6

• https://www.rfc-editor.org/rfc/rfc2945
• http://srp.stanford.edu/design3.html
• https://pkg.go.dev/github.com/opencoff/go-srp
• https://github.com/tadglines/go-pkgs/blob/master/crypto/srp/example_test.go
• https://github.com/brutella/hc/tree/master/hap/pair