AudioOutput: Improvements

[HTRamsey]

Modernizes AudioOutput with new functionality from Qt6.6.

• The queue is now handled internally in the QTextToSpeech object.
• Now available to use from QML.
• No longer dependent on QGCApplication making it an isolated utility available everywhere with a singleton using static methods.
• Inherits from QTextToSpeech making all functions available.
• Makes use of a QHash for faster translations
• Uses InvokeMethod for thread safety

[DonLakeFlyer]

This one seems a little odd: "Hey" for "A". Isn't that wrong? Might as well fix that.

[HTRamsey]

I checked with espeak on linux and I think you can just do "A.D.S.B.", "I.D.", "E.K.F.", etc. I don't know if that's standard though

[DonLakeFlyer]

MockLink has a "send status text" option which you could hack into and change the one that is spoken to test it out. I can test it on Mac.

https://github.com/mavlink/qgroundcontrol/blob/master/src/comm/MockLink.cc#L1377

[DonLakeFlyer]

I verified that "A.D.S.B" is spoken correctly on the Mac. I had to change the MAV_SEVERITY_NOTICE text in MockLink to test. The "#" status text isn't causing it to talk for some reason. Not sure if there is a bug there, I'll look.

[HTRamsey]

It also works on Android, so I guess we can try that to simplify things and if anybody has any issues we can change it back