ergodox_ez: Update the algernon keymap to v1.2

ergodox_ez: Update the algernon keymap to v1.2

Noticeable changes since the last pull request:

* The forced NKRO mode can be easily toggled off at compile-time, to
  make the firmware compatible with certain operating systems.
* The `:;` key has changed behaviour: to access the `;` symbol, the key
  needs to be double-tapped, instead of shifted.
* The `=` and `\` keys were swapped, `=` moved to the home row, on both
  the **base** and the **experimental** layers.
* The arrow and navigation keys were redone, they are now more
  accessible, but the navigation keys require an extra tap to access.
* The **Emacs** layer is gone, replaced by a simplified
  **navigation and media** layer.
* `LEAD v` types the firmware version, and the keymap version.
* On the **experimental** layer, the `L` and `Q`, and the `K` and `G`
  keys were swapped.
* The **Steno** layer gained a few more `#` and `*` keys, to make it
  easier on my fingers.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>