Simple extended space cadet (#5277)

* Simplifying and Extending Space Cadet to work on Ctrl and Alt keys

* PR Review feedback

* Reverting back to keycodes

quantum/quantum.h

@@ -131,6 +131,10 @@ extern uint32_t default_layer_state;
     #include "process_terminal_nop.h"
 #endif
 
+#ifdef SPACE_CADET_ENABLE
+  #include "process_space_cadet.h"
+#endif
+
 #ifdef HD44780_ENABLE
     #include "hd44780.h"
 #endif