Add a setting to hide unread messages badges. (#2412)

* Add a setting to hide grey unread messages badges.

* Move room badge logic to be built in the view model instead of in the view.

* Move setting into DeveloperOptions.

ElementX/Sources/Screens/Settings/DeveloperOptionsScreen/DeveloperOptionsScreenModels.swift

@@ -51,6 +51,7 @@ protocol DeveloperOptionsProtocol: AnyObject {
     var mentionsBadgeEnabled: Bool { get set }
     var roomListFiltersEnabled: Bool { get set }
     var markAsUnreadEnabled: Bool { get set }
+    var hideUnreadMessagesBadge: Bool { get set }
     
     var elementCallBaseURL: URL { get set }
 }