Add Bootmagic Lite to QMK (#4215)

Add Bootmagic Lite to QMK (#4215)

* Preliminary additon of bootmagic lite functionality

* Cleanup code

* Clean up bootmagic code

* Add documentation and clean up code

* Make 'lite' an option for BOOTMAGIC_ENABLE

* Update Templates with note about Bootmagic Lite option

* Detect Debounce variable

* Make sure debounce is a non-zero number

* Capitalize Bootmagic

* Capitalize bootmagic

* Update wording

* Re-add EEPROM reset, by popular demand

And add eeprom-less version to drashna userspace for his sanity

* Fix spacing

* Set BOOTMAGIC_ENABLE to use full/lite/off

And default yes to "full" for compatibility

* Add Bootmagic lite info to templates

* Remove text from makefiles

* Cleanup of makefile

* mention yes in bootmagic docs

* Wordsmitthing the docs

* Fix white spaces

* Readd default bootmagic setting, because it's necessary