[docs] Add a guide about `tauri::State`.

[anshul-raman]

Managing state of the application is a very common problem. Consider adding a section on managing state of the application in rust on this page.

The documentation is available in docs.rs but linking this page in features section of the main website will be more helpful.

[amrbashir]

other than this https://tauri.app/v1/guides/features/command#accessing-managed-state?

[anshul-raman]

I might have missed that. Sorry for this. Still a separate section with detailed example like in the docs.rs page would be helpful.

[Laegel]

Yeah, this piece of documentation is hidden in the page @amrbashir linked, not something you can find from a higher browsing level (the search doesn't give us many clues, too). I believe it deserves a dedicated page, I'll do it.

[FabianLars]

i think @lucasfernog works on this, or at least planned to do 😄