Generalize Tap Dance Layer functions (#6629)

* made tapdance dual_role general

* updated original dual_role functionality

* added toggling layer example

* Fix dual role and add alias

* Update docs about new layer tap dances

* Fix up based on feedback

.vscode/settings.json

@@ -8,10 +8,12 @@
         "**/*.hex": true
     },
     "files.associations": {
-        "*.h": "c",
-        "*.c": "c",
-        "*.cpp": "cpp",
-        "*.hpp": "cpp",
-        "xstddef": "c"
+      "*.h": "c",
+      "*.c": "c",
+      "*.cpp": "cpp",
+      "*.hpp": "cpp",
+      "xstddef": "c",
+      "type_traits": "c",
+      "utility": "c"
     }
 }