Push to alternative registry than Docker Hub

[samip5]

Docker hub has very limiting rate-limits, please consider pushing to another registry.

[Nold360]

Thanks for the issue, i already was thinking about this & guess we'll switch to ghcr, as it seems as one of the "cooles" registries currently. But first i want to work on the CI pipeline in general.

So this will be after or while working on 16

[Nold360]

Yea, we'll switch soon[tm] https://blog.alexellis.io/docker-is-deleting-open-source-images/