Implement room v12 (#943)

**Does not yet work!** Currently, state resolution does not correctly resolve conflicting states. Everything else appears to work as expected, so stateres will be fixed soon, then we should be clear for takeoff.

Also: a lot of things currently accept a nullable room ID that really just don't need to. This will need tidying up before merge. Some authentication checks have also been disabled temporarily but nothing important.

A lot of things are tagged with `TODO(hydra)`, those need resolving before merge. External contributors should PR to the `hydra/public` branch, *not* ` main`.

---

This PR should be squash merged.

Reviewed-on: https://forgejo.ellis.link/continuwuation/continuwuity/pulls/943
Co-authored-by: nexy7574 <git@nexy7574.co.uk>
Co-committed-by: nexy7574 <git@nexy7574.co.uk>

src/database/map/insert.rs

@@ -227,7 +227,7 @@ pub fn insert_batch<'a, I, K, V>(&'a self, iter: I)
 	let write_options = &self.write_options;
 	self.db
 		.db
-		.write_opt(batch, write_options)
+		.write_opt(&batch, write_options)
 		.or_else(or_else)
 		.expect("database insert batch error");