Establish team charters

[ehuss]

The core team previously started a process to establish charters for all teams. However, it wasn't finished. I would like to see a central place (my preference is the Forge) which contains basic charters for all of the teams which would answer the following:

• The team's mission and responsibilities
• Requirements for team membership, and the process to get involved
• Contact information so that someone can find where the team does its work (GitHub repos, Zulip streams, etc.)

As an extension to this, I think it would be good to have suggestions on having teams document their processes. My preference would be for teams to decide where and how that is documented, but having some starting templates could be helpful for standing up teams and making it clear what people's expectations should be.

A consideration is what gets chartered (teams, working groups, etc.).

There's tons of background here, but I will just drop a few links for now:

• https://github.com/rust-lang/governance — Contains some initial charters and templates.
• https://github.com/rust-lang/leadership-council/tree/main/committees — Council committee charters
• https://doc.crates.io/contrib/team.html — Cargo's charter.
• https://github.com/rust-lang/style-team/blob/master/charter.md — Style team charter
• https://github.com/rust-lang/keyword-generics-initiative/blob/master/CHARTER.md — Keyword generics charter
• https://github.com/rust-lang/rfcs/pull/2979 — Libs charter?
• https://hackmd.io/@rust-libs/HkgFCFWku — Libs impl charter?
• https://github.com/rust-lang/project-error-handling/blob/master/CHARTER.md — Project error handling charter
• https://rust-lang.github.io/wg-async/CHARTER.html — async charter
• https://rust-lang.github.io/dyn-upcasting-coercion-initiative/CHARTER.html — dyn upcast charter
• https://github.com/rust-lang/moderation-team/blob/master/moderation-team-charter.md — Moderation team charter
• https://github.com/rust-lang/rustup/wiki/Rustup-working-group-charter — Rustup
• https://github.com/rust-lang/project-deref-patterns/blob/master/CHARTER.md — project-deref-patterns

(There's stuff I'm missing...)

I would like to keep this issue focused on documenting existing team missions, and not to grow to more general considerations about what Rust's governance structure should look like (#33), definitions of different structures (teams, sub-teams, working-groups, project-groups), etc.