Use receipts `event_stream_ordering` column, remove joins to `events`

[matrixbot]

This issue has been migrated from #13918.

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Follow up to: matrix-org/synapse@cdbb641

This relies on the completion of the background task introduced by the above change. I suggest that we leave this in draft for N(?) releases and then force the migration similar to matrix-org/synapse@da41a7c#diff-ddb3c5844daede09acca491cc04a3740730179fca1fa75aa25b921727209947a, probably with an appropriate upgrade note at the time.

Signed off by Nick @ Beeper (@Fizzadar).

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file.
• Pull request includes a sign off
• Code style is correct
  (run the linters)