Clarify project director eligibility requirements

[eholk]

During the Fall 2023 project director elections, we had late-breaking questions around how "employment" is interpreted for the purposes of employment limits and around the legal requirements for candidates to disclose their names. At a minimum, we need to clearly document these requirements. We should also consider whether changes to these requirements are possible and desirable, as they significantly constrain who is able to serve in this role and makes it difficult to achieve other goals around diversity.

[ehuss]

Some past discussions that touch on the problem of interpreting employment:

• Project Director Elections: https://rust-lang.zulipchat.com/#narrow/stream/392734-council/topic/Project.20Director.20Elections
• Project Director Employment/Affiliation: https://rust-lang.zulipchat.com/#narrow/stream/392734-council/topic/Project.20Director.20Employment.2FAffiliation
• Project Director Temporary Substitution: https://rust-lang.zulipchat.com/#narrow/stream/392734-council/topic/Project.20Director.20Temporary.20Substitution
• Rust Project Affiliation Limits: https://hackmd.io/@rust-leadership-council/BJMOxfP5p
• Meeting minutes regarding affiliation limits:
  • https://github.com/rust-lang/leadership-council/blob/HEAD/minutes/sync-meeting/2023-11-10.md
  • https://github.com/rust-lang/leadership-council/blob/HEAD/minutes/sync-meeting/2024-02-16.md

Not noted here, but I think we've also discussed trying to unify the employment interpretation for both the Leadership Council and the Foundation board.

[eholk]

Adding this to the project board's short list since we want to get this done before the next round of PD elections.