Add option to enable to-device-encryption (#3167)

* enable to-device-encryption

* add logging for key provider

* make rooms encrypted

* add dev setting to choose to-device or room encryption

* add indicator when to-device is used.

src/settings/settings.ts

@@ -117,4 +117,10 @@ export const useNewMembershipManagerSetting = new Setting<boolean>(
   "new-membership-manager",
   true,
 );
+
+export const useExperimentalToDeviceTransportSetting = new Setting<boolean>(
+  "experimental-to-device-transport",
+  false,
+);
+
 export const alwaysShowSelf = new Setting<boolean>("always-show-self", true);