Keymap: Revamp replicaJunction keymaps (#3589)

* Revamp replicaJunction keymaps

Updates both the replicaJunction Ergodox and Atreus keymaps and moves
most of the logic into a new user directory.

* Cleanup as requested in #3589

* Slightly increased TAPPING_TERM

* Fixed typo in #pragma once

* Fix TAPPING_TERM redefined in config.h

* Add include of replicaJunction.h

Due to the tap dance references, without this include, I was getting
compiler errors about both internal QMK items like
`qk_tap_dance_state_t` and constants defined in my replicaJunction.h
file like TD_LAYER_TOGGLE.

Also remove some commented-out code that defined an enum which has since
moved to replicaJunction.h.

users/replicaJunction/readme.md

@@ -0,0 +1,14 @@
+Copyright 2018 @<replicaJunction>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.