TPA-RFC-61: 2024 roadmap

check list:

• review last year's roadmap (wiki-replica@38b0e30e)
• find previous year's tickets, see what the process was (#40924 (closed))
• brainstorm ideas
• propose / RFC ( https://gitlab.torproject.org/tpo/tpa/wiki-replica/-/blob/6c1bcc305f3ec7d02077a4b0fc3f377739d1c903/policy/tpa-rfc-61-roadmap-2024.md)
• discuss in meeting / adopt

probably won't propose anything before january because we're swamped, but if time permits, maybe step 1-2 above?

/cc @gaba