Show currently running applications/controllers

[sfeilmeier]

From openems-gui created by sfeilmeier : OpenEMS/openems-gui#32

Bug Report or Feature Request (mark with an x)

- [ ] bug report -> please search issues before submitting
- [x] feature request

Desired functionality.

The user needs to be able to see, which controllers are currently working (self-consumption optimization, peak-shaving,...)