Adds the ability to cycle back to the previous credential with LIGHT.
Long pressing LIGHT activates the LED.
Co-authored-by: Matheus Afonso Martins Moreira <matheus.a.m.moreira@gmail.com>
* Move from .c to .h as needed for consistency.
* When missing from both, copy from pull request or wiki.
* When missing entirely, infer functionality from source code.