Display total input/output power

[Indy2222]

Show sum of incoming and used energy (i.e. power input and power output in Watts) in the details panel of HUD. Compute this as average over e.g. 30s over all selected units / buildings.

This might require modification of Battery component so it tracks cumulative received and spent energy (instead of current energy level).

This is blocked by:

• HUD: Add details to the info panel (right part of the screen) #397
• Energy (Version 1 / MVP) Tracking Issue #256

[github-actions]

There is no activity on the issue for some time.