feat: expose {time} to eventPost data, fix renamed tooltip

[imorland]

Fixes #0000

Changes proposed in this pull request:
DiscussionRenamedPost used the old style tooltip method, plus the tooltip was triggered by hovering anywhere on the text line. We now use the Tooltip component, and only on the discussion title itself.

Adds time to EventPost attrs, enabling the use of it in translations for event posts easily. See attached screenshots for core/bundled usages.

Reviewers should focus on:

Screenshot
Before:

After:

Updated translations using the time attr

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).
• Core developer confirmed locally this works as intended.
• Tests have been added, or are not appropriate here.

Required changes:

• Related documentation PR: (Remove if irrelevant)
• Related core extension PRs: (Remove if irrelevant)

[askvortsov1]

I wonder if rel_time might be a better name; my first thought was that there's an "at" missing (e.g. x did y AT {time}), but that's not the case with humanTime