Proposal to move Rust std work to edk2-staging

["Ayush Singh" <ayushdevel1325@gmail.com>]

Hello everyone. The work on Rust std for UEFI has been progressing 
smoothly. Running Rust tests is now possible in it's entirety. The 
number of tests that fail is 133 (4 cause exception + 129 normal fails) 
out of 13,212 tests. Apart from the 4 tests that cause exceptions, most 
of the 129 other tests can be ignored since they are caused by needing 
dynamic linking and/or stack unwinding. So I think, it is time to start 
considering moving the project to a more appropriate repository before I 
open a PR upstream.


However, I do have some concerns regarding moving to edk2-staging:

1. Rust development workflow does not use Mailing lists and Patches. 
This might create friction for the purely `rustc` developers who might 
want to submit changes and are accustomed to PRs.

2. Rust project does not seem to care about maintaining a clean history 
(most of the merges are performed by bots in form of roll-up merges). 
This is much different from how edk2 projects are usually managed. The 
reason where this becomes a problem is having to do re-bases. While Rust 
provides strong guarantees for stability of user facing APIs, the 
internal std APIs are constantly changing. Combine that with no 
clean-history and the upstream PR will probably have to be re-based on 
latest master every few weeks (and it will likely need manual intervention).


I am planning on getting the code base ready for upstream PR before 15th 
August. The main things left to do is to publish new versions of 
`compiler_builtins` and `r-efi` crates, and refactor the code and UEFI 
documentation.


Yours Sincerely

Ayush Singh