[Playback] Process paths in slippi combo files relative to the config itself

[FluentCoding]

So that the configuration files for combos can be distributed together with the replays, the replays must be relative to the configuration file itself and not to the .exe of Dolphin (I'm doing this for clippi).

I tested it on Windows 10, with absolute and relative paths working perfectly, but I didn't test it on Unix (Linux/macOS) yet.

[NikhilNarayana]

Can I get an example zip to test with?

[vinceau]

I envision the zip structure could look something like this:

combos.zip
├── combos.json
└── slp
    ├── Game_1234.slp
    └── Game_5678.slp

I also think it's worth considering this a little bit deeper. It would be nice if there was some sort new file format which encompasses a set of SLP files, maybe call it SLPS, or something. It would be good if the Desktop app could also have file association support for this new format such that I could send someone a SLPS file, they can simply double click that file, and have it automatically unzip maybe in a temp folder, and open automatically load the JSON file into Dolphin. Better yet, if Dolphin could read the JSON and the SLP files without us even having to unzip it.

This could allow for much easier distribution of tournament SLPs. There's also potential for metadata to be included, so that player characters, game results, name tags could be easily extracted too.

But that can be for another day.