Move call buttons to the room header

This is to make some room in the composer for voice messages. The hangup behaviour is intentionally lost by this change as the VOIP UX is intended to rely on dedicated hangup buttons instead.

src/settings/Settings.ts

@@ -632,6 +632,8 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         default: 3000,
     },
     "showCallButtonsInComposer": {
+        // Dev note: This is no longer "in composer" but is instead "in room header".
+        // TODO: Rename with settings v3
         supportedLevels: LEVELS_DEVICE_ONLY_SETTINGS_WITH_CONFIG,
         default: true,
         controller: new UIFeatureController(UIFeature.Voip),