Playlists and error handling

[kmod-midori]

What have I done:

• Move event sinks to a separate class, similar to the Android code. This was done because sometimes we try to send out events before the sinks are ready, causing segfaults.
• Added support for playlists, except moving (I could not wrap my head around how that is done).
• Some try-catching, since Windows API sometimes throws in unexpected places, such as getters (mediaPlayer.PlaybackSession() can fail in event handlers).
• Updated some of the std::get_if calls, since according to docs, numbers are encoded as int32_t when they are small enough, and trying to do std::get_if<int64_t> on small values does not work (they are distinct types).
• Formatting, which was done by Visual Studio before I realized that it was too late.

I don't write a lot of C++ (mostly Rust), but this code works in my product (which relies heavliy on playlists) without crashing, so please review carefully before merging.

[bdlukaa]

Awesome work! I just tested it and it works in the example/example_playlist.dart app!

Tho, it sometimes crashes, so there must be a memory leak somewhere! I've experienced crashes before, mostly related to int-32 and int-64 casts.

Also, when the app doesn't crash, it prints this to the console
[just_audio_windows] Broadcast event error: Não há suporte para esta interface (there isn't support for this interface)

[kmod-midori]

Other WinRT APIs experience similar problems that if you try to obtain information in event handlers, they sometimes fail with strange exceptions (sometimes even fail with OK). The only way to handle this is to catch and ignore them, since not catching may crash the process.

We need to use Visual Studio to launch the project, which attaches Windows' native debugger. I think we are still having some issues related to memory and/or exceptions, but only the debugger will tell us.