Add toggle for the 1PS functionality

[lokka30]

Allows server owners to just use the 'clear phantom status on sleep' and 'clear weather on sleep' functionality of SleepFixer, so they can combine it with the 'sleeping percentage' gamerule and achieve X-player sleep.

This is achieved by adding a config option which toggles whether the player sleeping ignored functionality is used.

Suggested by Frog42

[lokka30]

I will leave this issue open as a very simple first contribution someone can make to SleepFixer if they're interested.