Show current usage in the menubar icon

[mikeage]

Is your feature request related to a problem? Please describe.
It would be very nice if we could add the current power draw (in watts) to the menubar icon. Either via a selector, or perhaps even a template system to customize what's displayed (compare Coconut Battery's customization for a very nice alternative)

Describe the solution you'd like
This ^^^^

Describe alternatives you've considered
Keeping Coconut Battery running, which I do. For now.

Additional context
n/a