Currently only handles the vanilla OBS case of two possible codecs, i.e.
it won't list multiple listed supported codecs as alternatives in the
warning message; also doesn't verify that the listed codecs are actually
available in OBS
Other than that it supports multiple "supported audio codec" entries
in services.xconfig per service, in case anyone wants to white list
both MP3 and AAC for their service:
```
recommended : {
"supported audio codec" : "MP3"
"supported audio codec" : "AAC"
}
```
Properly hide the "Keep recording" checkbox when switching to file
output only, update the Start Streaming/Start Recording buttons when
switching modes in the settings.
Move the keep recording setting from global.ini to Broadcast Settings
(profile dependent), make it default to off, comment out the old
dashboard link code for now.
