[metrics-team] A new home for the Metrics Timeline?

[David Fifield]

The metrics timeline is a database of events that could have an effect
on Tor Metrics graphs. It was formerly maintained on the Trac wiki.
https://lists.torproject.org/pipermail/metrics-team/2020-August/001153.html
Metrics tools parsed the wiki markup and used the information to make
the "Related events" tables under graphs on metrics.torproject.org.

But now the Trac wiki is read-only, so the timeline cannot be updated.
KuroNeko wanted to add an event but couldn't:
https://lists.torproject.org/pipermail/metrics-team/2020-August/001153.html

I was to discuss finding a new home for the metrics timeline. Here are a
couple of options.

OPTION 1: Use a wiki page on GitLab.
There are already a couple of copies of the timeline on the GitLab wiki,
one automatically migrated with slightly broken markup, and one cleaned
up by Cecylia.
https://gitlab.torproject.org/legacy/trac/-/wikis/doc/MetricsTimeline
https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/Censorship-Events
PROS: In principle, interested volunteers can request a GitLab account
and edit the wiki. Doesn't require any special tools to edit.
CONS: GitLab markup is different from Trac markup, so new parsers will
have to be written. It's easy to break the format by accident.

OPTION 2: Use a CSV file in a Git repository.
My thinking in putting the timeline on a wiki page was to enable the
public to add events, without needing to go through a burdensome process
to set up credentials. In practice, though, I think not many took
advantage of it. We could instead host it in a Git repository.
PROS: Doesn't require a specialized parser. More independent of the
GitLab wiki; can host tools and documentation in the same repository.
Better versioning.
CONS: Higher barrier to contribution. A little less human-editable.

Any other options?

In the meantime, I have been keeping track of a few new events just in a
local copy of
https://trac.torproject.org/projects/tor/wiki/doc/MetricsTimeline?format=txt