Adding proper GUI / code for custom model support (gui reimplementation from mcyoung)

[Teotia444]

This PR is a re-implementation of a re-implementation from McYoung that contains code for a custom model subpage.

(from mcy's pr) The PR contains :

1. Code for doing the patching. Right now it patches Link.szs and some files for voice clips. It should probably also patch the files for the map icon, too, but I don't know what the right destination for those is.
2. Adds a way to select a custom model in the Aroma UI. The current mechanism is not ideal or efficient, but unless people have hundreds of models I doubt the O(n log n) overhead will be noticeable. I have made it so that you can have multiple models to choose from.
   This PR still doesn't contain the desktop code, but i'll probably open another one containing just that.

Very quick video showing how the added tabs look :
https://github.com/user-attachments/assets/473a9408-056b-4dca-a6b9-efd0b420c6e3
(can provide more if needed)

[mcy]

std::vector<fspath> models;
for (auto& dirent : std::filesystem::directory_iterator(Utility::get_models_dir())) {
  if (dirent.is_directory()) models.push(dirent.path());
}
std::sort(models.begin(), models.end()); // readdir order isn't deterministic

[Teotia444]

thanks, much cleaner!

[mcy]

Perhaps this should not overload the value of modelName, since people will get confused if they name a model random...

[Teotia444]

I've replaced "random" with "?" as it is a forbidden character in Windows, which is already less likely to cause issues. I agree tho, modelName should probably not be overloaded and i should just add a new attribute, i'm lazy tho :)

[SuperDude88]

Just tossing ideas out since I haven't really dug through the old code/new code in a while -- but I think logically an empty string would make sense for a random model, basically equivalent to "no specific one provided"

That assumes an empty name isn't used as an error/validity condition anywhere, but honestly the error handling in my original custom model class is already bad so I'll need to rework that part of the system at some point regardless