MSU-1: Add support for .ogg files, and the .msu1 zip-file format

[Gutawer]

This PR contains two commits.

The first implements support for loading .ogg files as an alternative to .pcm files currently supported by emulators for MSU-1 since they are about 10x less heavy in file size than these uncompressed .pcm files. Behavior here is to attempt loading a .ogg if a .pcm is missing. It also supports a LOOPSTART comment in the .ogg files which contains which sample to loop from - this seems to be somewhat of a de facto standard for use cases that need this?

The second commit implements support for a ".msu1" file format that (at least?) snes9x supports, which is a .zip file in disguise laid out like this:

> zipinfo Something.msu1
Archive:  Something.msu1
Zip file size: 31525839 bytes, number of entries: 3
-rw-r--r--  3.0 unx  4194816 b- stor 24-Apr-03 21:59 program.rom
-rw-r--r--  3.0 unx 27330704 b- stor 23-Jan-27 22:39 track-42.ogg
-rw-r--r--  3.0 unx        7 b- stor 24-Apr-11 22:43 data.msu
3 files, 31525527 bytes uncompressed, 31525527 bytes compressed:  0.0%

This format is easier to distribute to the end-user especially since (if stored as an uncompressed .zip like in my example) it can still be encoded as a .bps patch compared to the base rom.

In particular the format as snes9x interprets it only cares about whether files end with -<track number>.(ogg|pcm) or .msu for music or data files respectively, so I've implemented that.

To achieve that this modifies the pcm reader and general msu-1 to use VirtualFiles so that they can load from within an archive. I believe I've implemented that in a way that the data is still streamed if it's not from an archive, but unfortunately .zip-compressed data isn't seekable so it needs to be loaded into memory first?

Happy to address any code quality concerns, this is the first time I've really had a more in-depth look at the codebase.