add proxy registries for common registries

[ostempel]

Description

Closes #210

Added proxy registries of common registries in order to consecutively cache images.

Also tried to start proxy registries before control-plane startup in order to cache default k8s images, but this didn't work.

[Gerrit91]

I think it's good!

Was first thinking to somehow use the images from the host docker daemon first, but after looking at how this could be done, I think that his solution is nice and clean. After some time we maybe have to cleanup these registries a bit.

[ostempel]

Also checked other solutions like nexus and harbor. They require advanced configuration and are too heavyweight for this use-case.

In order to cleanup the registries I tried to find a solutions which supports deleting unused images. Problem here is, that images just support createdAt and no lastUse date. Therefore we now just support static volume size cleanup. Meaning the volume of a proxy gets deleted if it exceeds a specific threshold.