[applets/batterymonitor] Introduce power profile icons
Power profile labels are gone and replaced with only two descriptive
icons, and now there's only one of label at the top of the slider,
which aligns with what
Padding of the header is handled now entirely within the header itself.
|Narrow - English|
|Narrow - Russian|
|Narrow - German|
As you can see, this change may affect strings hungry languages, which unsurprisingly Russian is one of, and surprisingly German is not one of.