Multiple Widgets: consider making batteries' type name (and perhaps more) info query-able

[PeterRed4091]

This would likely be done under a new query key, because the vanilla query key only processes int[].
I made some attempts before (see #2 and #10), but they weren't satisfactory.
Still, I would like to see this done so that we have a better interface regarding battery-widget things.

[PeterRed4091]

About the "perhaps more" part of the suggestion: An example is the capacity of holders to tell apart the different empty holders, if that is desirable.