Add keymappings for several utility functions (#3536)

* - map fn+m to mute and unmute the external notification module
- map fn+t to be an alternative for the TAB key

* add whitelist to inputbroker

* (maybe) sweet-talking t-deck into tabbing...

* now for real - back in Kansas

* More fancy mappings

---------

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/modules/ExternalNotificationModule.h

@@ -38,6 +38,9 @@ class ExternalNotificationModule : public SinglePortModule, private concurrency:
     void setExternalOff(uint8_t index = 0);
     bool getExternal(uint8_t index = 0);
 
+    void setMute(bool mute) { isMuted = mute; }
+    bool getMute() { return isMuted; }
+
     void stopNow();
 
     void handleGetRingtone(const meshtastic_MeshPacket &req, meshtastic_AdminMessage *response);
@@ -56,6 +59,8 @@ class ExternalNotificationModule : public SinglePortModule, private concurrency:
 
     bool isNagging = false;
 
+    bool isMuted = false;
+
     virtual AdminMessageHandleResult handleAdminMessageForModule(const meshtastic_MeshPacket &mp,
                                                                  meshtastic_AdminMessage *request,
                                                                  meshtastic_AdminMessage *response) override;