Updates send_string functionality, adds terminal feature (#1657)

* implement basic terminal stuff

* modify send_string to read normal strings too

* add files bc yeah. working pgm detected

* pgm detection apparently not working

* adds send string keycodes, additional keycode support in send string

* implement arguments

* [terminal] add help command

* [terminal] adds keycode and keymap functions

* [terminal] adds nop.h, documentation

* update macro docs

quantum/audio/song_list.h

@@ -248,4 +248,7 @@
     Q__NOTE(_GS5),     \
     HD_NOTE(_C6),
 
+#define TERMINAL_SOUND \
+    E__NOTE(_C5 )
+
 #endif