Fix https://github.com/matrix-org/matrix-public-archive/issues/59
Other updates:
- Update tests to use `/roomid/room1/date/2022/01/03` format instead of trying to retrofit the weird alias stuff on there. Which also makes the fancy to actual URL utilities much more simple.
- Update to specify `archiveMessageLimit` in the test case because pages have different number of events depending on if we are against a boundary, hidden events, etc.
- Less test bulk
- Single source of truth: there is no mismatch between the comment and the expectations (we already caught a few mistakes in the conversion thanks to this benefit)
- Easier to maintain and update
Eric Eastwood