Add VIA keymap for Plaid-Pad (#10057)

* Add via keymap for Plaid-Pad

- Add VIA support for the Plaid-Pad
- Changes Vendor ID and Product ID (to follow VIA's guidelines)

* Add extra encoder pads for rev1.1

* Change Product Id from pp to PP (hex value)

* improved readme

- detailed informations about rotary encoder, bootloader and firmware

* Improved encoder informations in via keymap

* Improved encoder infos and code in default keymap

* add revision folder for rev1 and rev1.1

* change encoder assignment for defaul a via keymap

* Update keyboards/keycapsss/plaid_pad/config.h

* change revision number

* Update keyboards/keycapsss/plaid_pad/rules.mk

* Update keyboards/keycapsss/plaid_pad/rules.mk

* Update keyboards/keycapsss/plaid_pad/rules.mk

* Update keyboards/keycapsss/plaid_pad/rules.mk

* Update keyboards/keycapsss/plaid_pad/readme.md

* add license to header of *.h and *.c files

* remove the list of alternate bootloaders

- due to the pr checklist

* Update keyboards/keycapsss/plaid_pad/rules.mk

keyboards/keycapsss/plaid_pad/keymaps/via/rules.mk

@@ -0,0 +1,4 @@
+VIA_ENABLE = yes
+LTO_ENABLE = yes
+EXTRAKEY_ENABLE = no
+MOUSEKEY_ENABLE = no