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/input/kbI2cBase.cpp

@@ -217,7 +217,11 @@ int32_t KbI2cBase::runOnce()
                 e.kbchar = 0xb7;
                 break;
             case 0x90: // fn+r
+            case 0x91: // fn+t
             case 0x9b: // fn+s
+            case 0xac: // fn+m
+            case 0x9e: // fn+g
+            case 0xaf: // fn+space
                 // just pass those unmodified
                 e.inputEvent = ANYKEY;
                 e.kbchar = c;