Keymap: Revamp replicaJunction keymaps (#3589)

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.