Add archived teams to v1 API

[Kobzol]

Required for rust-lang/www.rust-lang.org#2181. I decided to use a separate file and directory for the archived teams, rather than just adding an archived: bool field, for two reasons:

• It maintains backwards compatibility, e.g. for the Rust website, otherwise it would immediately start rendering archived teams in the governance section.
• It correponds to how we store the archived teams on disk in the team repo.

It is inconsistent how we represent archived repositories in the API output though, those have the archived bool.

[github-actions]

Dry-run check results

[WARN  sync_team] sync-team is running in dry mode, no changes will be applied.
[INFO  sync_team] synchronizing github

[marcoieni]

there's a merge conflict unfortunately

[Kobzol]

Rebased.