Duck Octagon V2 QMK Support (#2153)

Duck Octagon V2 QMK Support (#2153)

* Initial commit for Octagon V2 Support

This is still basically just a copy of lightsaver support with
names changed.

* Port xauser keymap from: https://github.com/xauser/tmk_keyboard/blob/xauser/keyboard/octagon_v2/keymap_common.h

* Temporary default keymap just to get things compiling

* Modify config.h to have the right keyboard info

* Partial port of xauser matrix code for octagon v2

* Fix readme.md
1. Fix link to geekhack GB
2. Add microchips
3. Add appropriate attributions

* Fix PORTD

* Intermediate fix to get LEDs working

* Update BACKLIGHT_AREAS enum

* Port the following:
backlight_set
backlight_toggle_rgb
backlight_set_rgb

and resolve dependencies in header files

* Port backlight_update_state to led_set_kb

* Change copyright notice author to MechMerlin

* Remove Rasmus keymap

* Get a default keymap that actually does something and let's you reset.

* Convert keymap into KC_XXXX format.

* Better formatting of the default keymap to make it more readable

* Fix keymap

* Get that Fn key working!

* Some code cleanup and small refactor

* Fix keymap in octagon_v2.h