[Keyboard] Add keyboard 7skb (#7468)
* Add keyboard 7skb
Add 7skb keyboard.
A 63 keys HHKB Layout keyboard.
Salicylic-acid3
* Update keyboards/7skb/keymaps/default/keymap.c
* Update keyboards/7skb/keymaps/default/keymap.c
* Update keyboards/7skb/keymaps/default/keymap.c
* Update keyboards/7skb/keymaps/salicylic/keymap.c
* Update keyboards/7skb/readme.md
* Update keyboards/7skb/readme.md
* Update keyboards/7skb/readme.md
* keymap update
Remove extra parts
* Delete rules.mk
* Update keyboards/7skb/rev1/rev1.c