fix room version comparisons

Fixes a set of bugs introduced by 00b77144c1,
where we replaced explicit `RoomVersionId` matches with `version < V11`
comparisons. The `Ord` impl on `RoomVersionId` does not work like that,
and is in fact a lexicographic string comparison[1]. The most visible
effect of these bugs is that incoming redaction events would sometimes
be ignored.

Instead of reverting to the explicit matches, which were quite verbose,
I implemented a `RoomVersion` struct that has flags for each property
that we care about. This is similar to the approach used by ruma[2] and
synapse[3].

[1]: 7cfa3be0c6/crates/ruma-common/src/identifiers/room_version_id.rs (L136)
[2]: 7cfa3be0c6/crates/ruma-state-res/src/room_version.rs
[3]: c856ae4724/synapse/api/room_versions.py

src/utils/error.rs

@@ -80,6 +80,8 @@ pub(crate) enum Error {
     AdminCommand(&'static str),
     #[error("from {0}: {1}")]
     Redaction(OwnedServerName, ruma::canonical_json::RedactionError),
+    #[error("unsupported room version {0}")]
+    UnsupportedRoomVersion(ruma::RoomVersionId),
     #[error("{0} in {1}")]
     InconsistentRoomState(&'static str, ruma::OwnedRoomId),
 }
@@ -146,6 +148,10 @@ impl Error {
                     _ => StatusCode::BAD_REQUEST,
                 },
             ),
+            Self::UnsupportedRoomVersion(_) => (
+                ErrorKind::UnsupportedRoomVersion,
+                StatusCode::INTERNAL_SERVER_ERROR,
+            ),
             Self::Conflict(_) => (Unknown, StatusCode::CONFLICT),
             _ => (Unknown, StatusCode::INTERNAL_SERVER_ERROR),
         };