Battery Percentage Switch

This feature brings the ability to show/hide battery percentage from the top bar, already present on Tweaks.

I totally agree with @lionirdeadman, on issue #1047 (closed), about people getting devided between Tweaks and Settings, because Tweaks not also provides essential settings for the people in general and advanced tweaks that may cause bugs.

I think this feature should be in settings because I don't feel I need to install open the system icons just to see the battery percentage.

This feature is marked as WIP, because I don't know yet where should exactly I put them.

In this picture I just put into energy saving menu, but I feel it should belong to the battery menu in the top. So I really appreciate giving feedback for this feature.