Document official Google calendar

[infinisil]

Let's document the permissions for the official Google calendar explicitly, so that people can make PRs to request changes to it. I asked @edolstra for the current permissions, which this PR is based on.

@edolstra @grahamc @rbvermaa @garbas @tomberek As the only people with access to manage permissions, you're being added as a code owner. The expectations are:

• You review and merge PRs proposing changes to it.
• The person merging also implements the change afterwards.
• No changes should be done without a PR.

This effectively makes this documentation the source of truth for calendar permissions. If you're okay with doing this, please approve this PR.

I'd say that those who don't react to this PR until 2024-12-23 (next Monday) can be assumed to not need access to manage permissions anymore, and would ask the others to remove them before we merge this PR. This ensures that everybody is willing to actively help maintain it.

[rbvermaa]

Please feel free to remove me

[edolstra]

@rbvermaa Thanks, I've removed you. @infinisil Can you update the PR?

[infinisil]

@edolstra @tomberek Since only you approved, please remove Rok's and Graham's calendar access. I updated the PR to reflect that, then we can merge it

[Ericson2314]

Thanks for doing it, I do always forget where these links are

[roberth]

Needs rebase for CI, it seems.

[infinisil]

Oh and ideally we'd also have one more SC approval, to solidify the google calendar as something official