Add feature flag for prototypes

src/settings/Settings.ts

@@ -109,6 +109,12 @@ export interface ISetting {
 }
 
 export const SETTINGS: {[setting: string]: ISetting} = {
+    "feature_communities_v2_prototypes": {
+        isFeature: true,
+        displayName: _td("Communities v2 prototypes. Requires compatible homeserver. Highly experimental - use with caution."),
+        supportedLevels: LEVELS_FEATURE,
+        default: false,
+    },
     "feature_new_spinner": {
         isFeature: true,
         displayName: _td("New spinner design"),