feat(wm): add additional manage rules

Following on from 8ffe6f78b7, this commit
introduces a command to add rules to forcibly manage windows that don't
get picked up by the rough heuristics that are able to target most
windows for management in Window.should_manage.

Since there is again no overlap (or at least, no undesired overlap)
between executable names and classes, I'll keep both class and exe names
in a single lookup vec.

re #16

komorebi-core/src/lib.rs

@@ -61,6 +61,7 @@ pub enum SocketMessage {
     FloatExe(String),
     FloatTitle(String),
     WorkspaceRule(ApplicationIdentifier, String, usize, usize),
+    ManageRule(ApplicationIdentifier, String),
     IdentifyTrayApplication(ApplicationIdentifier, String),
     State,
     FocusFollowsMouse(bool),