R&D EASY-RES AIT HIL

[sfeilmeier]

This Pull-Request is Work-In-Progress for the EASY-RES research project. It adds an implementation for the "AIT HIL Controller" to set a Power-by-Frequency (P-by-F) curve using SunSpec Model 134 and a respective Controller, that allows defining a Schedule of curves.

[JohnVidler]

Multiarch images successfully building and deployed with these patches against the develop branch. (building/testing for linux/amd64, linux/arm64 and linux/arm32v7 docker images)

I'm currently working on getting these tested on the EASY-RES testbed, and will report back here with any issues.