[Keymap] Jarred's Plaid keymap (#6049)

* Add my plaid keymap

* Move planck / plaid keymaps to common layout folder

layouts/community/ortho_4x12/jarred/readme.md

@@ -0,0 +1,22 @@
+# Jarred's ortho 4x12 keymap
+
+[User space](../../../../users/jarred/readme.md)
+
+Boards used on:
+- [Planck](../../../../keyboards/planck/readme.md)
+- [Plaid](../../../../keyboards/plaid/readme.md)
+
+# Plaid build notes
+
+Enter Bootloader:
+Press Reset / Press Boot / Release Reset / Release Boot
+
+Install libusbK driver for usbasp:
+https://zadig.akeo.ie/
+
+make plaid:jarred:program
+
+Press Reset
+
+https://github.com/hsgw/plaid/blob/master/doc/en/bootloader.md
+https://github.com/hsgw/plaid/blob/master/doc/en/firmware.md