Make the initial room selectable using search params

src/app.js

@@ -14,6 +14,8 @@ import * as humanhash from "humanhash"
 import jdenticon from "jdenticon"
 
 const DEFAULT_ROOM = "imperial"
+const initialRoom =
+  new URLSearchParams(location.search).get("room") || DEFAULT_ROOM
 
 const MIN_PRESSURE_FACTOR = 0.1
 const MAX_PRESSURE_FACTOR = 1.5
@@ -533,4 +535,4 @@ window.addEventListener("unload", () => {
   }
 })
 
-tryRoomConnect(DEFAULT_ROOM)
+tryRoomConnect(initialRoom)