[Keyboard] Create KBDFans directory (#5025)

* move over kbd19x into the kbdfans directory

* move over kbd4x into the kbdfans directory

* move kbd66 into the kbdfans directory

* move the kbd6x into the kbdfans directory

* move kbd8x into the kbdfans directory

* move kbd75 into the kbdfans directory

* move kbd67 into kbdfans directory

* add a fairly sparse readme for kbdfans directory

* update make instructions for keyboards and add the Complete Newbs Guide to readmes that was missing it

* get kbd75 compiling again

* remove repetitive #defines of KC_NO and KC_TRNS when QMK_KEYBOARD_H is already included in KBD75

* add links to kbdfans readme

* fix some readme formatting

* there is no reason to have two different keymaps with such a small difference, condensing to one

* turning on backlights by default

* enable backlight by default for kbd66

* noticed that the kbd75 had caps lock led code in every keymap. Moved it out to the keyboard.c so everyone can partake.

* Update keyboards/kbdfans/kbd66/readme.md

Co-Authored-By: mechmerlin <30334081+mechmerlin@users.noreply.github.com>

* update readme link ordering