Add dioxus build utility

[ormoyo]

Dioxus is a UI framework for rust.
I just made this to run the framework's CLI tool for hot reloading from inside neovim.

[Zeioth]

Thank you for the good PR!! It's ok to hardcode the commands as you are doing, as there is nothing to parse.

TODOS:

• bau-utils: Let's also add the option serve.
• bau/dioxus: We must read the env var DIOXUS_CLEAN_FIRST, and run dx clean when it's true (see bau/cmake.lua)