Write Storage Example

[flibitijibibo]

This ticket is designed to supercede #12400.

The documentation in SDL_storage.h is a bare minimum program that shows a working example, but not the best example. I need to write something that shows what real-world storage interaction looks like, with a follow-up example that shows how it can be leveraged with remote storage systems (particularly ISteamRemoteStorage).

This definitely isn't going to make it to the end of the year, unless something comes up where I can forcibly put this at the top of my list... I could probably prioritize this if I had a Steam AArch64 setup, but that's not going to be public until next year.