[IPlayer et al.] Replace various GetAudio... methods with one GetAudioStreamInfo method

This PR removes

 * ```GetAudioStreamLanguage(int iStream, CStdString &strLanguage)```
 * ```GetChannels()```
 * ```GetAudioCodecName()```
 * ```GetAudioStreamName(int iStream, CStdString &strStreamName)```

from all players and replaces them with ```GetAudioStreamInfo(int iStream, IPlayerAudioStreamInfo &info)```.

All affected places are adapted.

Since I'm on windows I have only check this. I could use some help/feedback from other platform devs.