[Keyboard] Add QUAD-H LB75 keyboard (#8607)

* Copy back old files from 9 months ago

* Delete unnecessary functions in lb75.c

* Remove LCD and MIDI config

* Modernize ancient files

* Update keymaps as necessary

* Move files to vendor folder

* Update readme to reflect changes

* Modernize makefile

* Remove split config

* Update keyboards/quad_h/lb75/keymaps/continuous_fnrow/keymap.c

* Update keyboards/quad_h/lb75/keymaps/via/keymap.c

* Update keyboards/quad_h/lb75/keymaps/divided_fnrow/keymap.c

* Update keyboards/quad_h/lb75/lb75.c

* Update lb75.c

* Update keyboards/quad_h/lb75/keymaps/continuous_fnrow/keymap.c

* Update keyboards/quad_h/lb75/readme.md

* Update keyboards/quad_h/lb75/keymaps/via/keymap.c

* Update keyboards/quad_h/lb75/keymaps/continuous_fnrow/keymap.c

* Update keyboards/quad_h/lb75/keymaps/divided_fnrow/keymap.c

* Update keyboards/quad_h/lb75/keymaps/divided_fnrow/keymap.c

* Update keyboards/quad_h/lb75/keymaps/via/keymap.c

* Add default keymap as required

* Update keyboards/quad_h/lb75/info.json

* Update keyboards/quad_h/lb75/info.json

* Update keyboards/quad_h/lb75/readme.md

* Update keyboards/quad_h/lb75/readme.md

keyboards/quad_h/lb75/readme.md

@@ -0,0 +1,15 @@
+# LB75
+
+![LB75](https://i.imgur.com/UNhskvMl.jpg)
+
+LB75 PCB for QUAD-H
+
+* Keyboard Maintainer: [ai03](https://github.com/ai03-2725)
+* Hardware Supported: The LB75 PCB
+* Hardware Availability: Private
+
+Make example for this keyboard (after setting up your build environment):
+
+    make quad_h/lb75:default
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).