[Keyboard] Add GTM Pad macropad (#7123)

[Keyboard] Add GTM Pad macropad (#7123)

* initial commit

begin development of Grand Theft Macro Pad (2key2crawl clone)

* Minor Changes

Changes to readme.md

Changes to config.h matrix pins

Changes to gtm.h layout

Changes to rules.mk

* initial commit

begin development of Grand Theft Macro Pad (2key2crawl clone)

* Minor Changes

Changes to readme.md

Changes to config.h matrix pins

Changes to gtm.h layout

Changes to rules.mk

* Update keyboards/sck/gtm/readme.md

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/readme.md

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Update keyboards/sck/gtm/rules.mk

Co-Authored-By: fauxpark <fauxpark@gmail.com>
* Changes to gtm.h

Changes to layout to be correct for matrix_cols and matrix_col_pins

* Minor Changes

Removed rotary encoder index in keymaps per suggestion