Enhancement: Use battery icon instead of label and status

[Erimus-Koo]

Describe the feature you'd like

There are several battery icons available in the Nerd Font, which display both the percentage and charging status. Mine is "JetBrainsMono Nerd Font".

Using them instead of the heart label and "AC" will save space and increase clarity.

Of course not everyone installed the nerd font, so there might be an alternative option such as "use-battery-icon".