This implements a simpler version of the wlroots logger for swaylock.
With this logger, the dependency on wlroots can be dropped. This also
adds a debug flag and disables debugging output by default
This implements customization for the indicator as proposed in sway#2788 with comments from sway#3367 in mind.
The default behaviour does not change exept for the caps lock text color.
Since these changes seem to be lost in the split I've remade them.
