This reverts commit 283ade8e33. This was supposed to come as a collection of commits, not squashed into one.
283ade8e33
Implements: [MSC4306](https://github.com/matrix-org/matrix-spec-proposals/blob/rei/msc_thread_subscriptions/proposals/4306-thread-subscriptions.md) (partially) What's missing: - Changes to push rules Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>