add option to recompute room state

Hopefully we can make use of this state resolution code for more stuff
in the future.

src/cli.rs

@@ -99,6 +99,14 @@ pub(crate) struct GetRoomStatesArgs {
     #[clap(flatten)]
     pub(crate) config: ConfigArg,
 
+    /// Recompute the room state instead of getting it from the caches
+    ///
+    /// Note that this can be VERY SLOW for some rooms. `#matrix:matrix.org`
+    /// has been seen to take around 30 minutes to solve on a 7950X, for
+    /// example.
+    #[clap(long, short)]
+    pub(crate) recompute: bool,
+
     #[clap(flatten)]
     observability: ObservabilityArgs,
 }