Removes the frontend glue module, instead the frontend state struct is allowed to be created by users. This doesn't solve Rust 2024 problems (although, since we're building c++ code anyways, we can always just stash the pointer there) but it's much cleaner.Some stuff is made to use pointers, this is just because I don't want to mess around with lifetime stuff right now (it all lasts as long as the app anyways)
