Support XCP files

[Ludko4444]

Xenia should be able to support XCP files (original xbox files on xbox marketplace).
The best way to support them would be indirectly:

1. Firstly we would decrypt XCP file to a normal xbox file.
2. Then we would run the xbox (decrypted) file.

Note: Not all XCP files are encrypted (for example GoD demos).

[Razzile]

Wasn't this (or rather support for Original Xbox games) part of our wontimplement list @gibbed ?

[gibbed]

Wasn't this (or rather support for Original Xbox games) part of our wontimplement list @gibbed ?

It was discussed on Discord and it basically:

XCP isn't meant for random access to load from it directly, it's a single stream of zlib data (once decrypted).

We could have UI options to decompress it into another file as a tool, but it's not something desirable to do that automatically given how large these files are.

Having it as an option would need to wait until we have more tools to put things into the UI so the user can invoke them as wanted.