Add support for building Rust-based flipper applications

[wiktor-k]

Hi,

I just started thinking about developing Flipper apps and noticed that the catalog mandates using uFBT.

I didn't see any open issues about that but I'm wondering what is your opinion on including Rust-based applications in the catalog?

From my experiments it seems they get built nicely with standard, stable Rust toolchain (the GitHub CI definition is pretty straightforward) but maybe you don't want to make your build environment more complex. Anyway, the catalog is really a big selling point for me so one way or another it'd be nice to know your opinion on the matter.

Thanks for your work, time and have a nice day! 👋