Add support for the new golem registry

[cryptobench]

I've tested this PR locally to check if everything is working as it should, and I have not come across any problems yet. I have mainly just changed the logic that is used when looking up an image.

There's 1 breaking change and that is that i've renamed image_hash in VmRepo to image as we are not solely relying on hashes in the future.

Please check it out and give comments.

[cryptobench]

AutoPEP8 is installed on my IDE. I wasn't aware that Yapapi follows a specific formatter type.