docs(codes): Add (key) codes documentation

Create codes documentation for standardized keys.

Closes #218.  Fixes #308.  Ref #21.

docs/src/data/hid-applications.js

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) 2020 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: CC-BY-NC-SA-4.0
+ */
+
+import usage from "../hid-usage";
+import * as pages from "./hid-usage-pages";
+
+export const keyboard = usage(pages.genericDesktop, 0x06);
+export const consumer = usage(pages.consumer, 0x01);