Add "Last updated" column in the table(s)

[yarikoptic]

primarily was interested in one for OSF: wanted to checkout the most recent'ish one, but impossible ATM.

For organization groups could be the latest among all repositories under that organization.

That would also harmonize display a bit since then OSF could become a table as well (and thus I could sort it)

[jwodder]

@yarikoptic Is this "last updated" field supposed to be when a repository was last updated on GitHub/OSF/GIN or when its entry in datalad-repos.json was last updated?

• If it's supposed to be when a repository was updated on GitHub/OSF/GIN, then, for GitHub at least (and possibly one or both of the others; I need to check) should the repository's updated_at or pushed_at timestamp be recorded? I don't know what causes updated_at to be updated, but the pushed_at timestamp for a repository can sometimes be the later of the two; for example, at the moment, for my repolist repository, the GitHub API reports an updated_at timestamp of 2023-11-01T15:33:02Z (two seconds after created_at) and a pushed_at timestamp of 2024-01-23T18:06:08Z.

[yarikoptic]

for the repository (not our entry). I guess let's take pushed_at for github. Note to myself: that timestamp would be after the date of the actual commit in the repo, so we indeed would be looking at the "most recently updated" (on the hosting portal) and not necessarily "most recently updated in git" (i.e. could be old commits pushed)