[Keymap] Add preonic/kjwon15 layout (#6812)

* Add my custom keymap

* Remove del key on left, Add pscr

* Move Audio MOD key to pass ctrl

* Change startup song

* Enable clicky sound

* Swap alt and gui

* Fix semitones

* Add mouse layer

* Change startup song

Additionally, fixup 5 halftones

* Add ctrl key to ctrl+click

* Move media keys to restore raise number keys

* Move mouse key layer switch

* Swap media keys as normal

* Fix music map

* Move mouse speed limit to correct position

* Move prtscr

* Align keycodes

* Add ctrl/esc, swap smart space keys

* Change colemak, dvorak into custom layout

* Fix pure mode (left space)

* Fix mouse mode interrupt

* Add Middle mouse click

* Add Lefthand mouse scroll

* Temporarily disable mouse speed

* Rename custom layout to kjwon15

* Change readme

* Apply suggestions from code review

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Apply suggestions from code review

* Apply suggestions from code review

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Update from default keymap's function

keyboards/preonic/keymaps/kjwon15/readme.md

@@ -0,0 +1,27 @@
+# Kjwon15's Preonic layout
+
+
+## It provides almost full functionality for linux
+
+It has screen capture key which is also used on sysq
+
+
+## Mouse layer
+
+Press left spacebar to activate mouse mode.
+Right hand to move cursor/scroll, Left hand to click
+
+
+## Dual function keys
+
+Right shift is also Enter key. If you press and hold, that key act as shift. But if you tap that key, It is enter key.
+If you want to press and hold enter key, Use left-bottom key. That is pure enter.
+
+## Blank layout
+
+If you want to lock your keyboard, switch to this layout. It also useful when you want to clean your keyboard without disconnecting USB.
+
+
+## Pure mode
+
+Dual function keys are so annoying when you playing game. Then use this layout