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.

[shadeofblue]

any such breaking changes should follow a proper deprecation process...

BUT, having said that, I don't think that we want to have it implemented that way - rather I think we'd like to explicitly differentiate tags from hashes

[cryptobench]

I agree on the deprecation process - i'm just unsure how it's usually done, so please do suggest what to do.

I just think there will be less struggle for requestors if they can just define a single parameter to the package, and insert either a hash or tagged image and then yapapi automatically handles it for them. If we decide to split it up anyway, wouldn't it be smart to include some kind of check to see if they've accidentally used a hash on the tag parameter and vice versa?

[cryptobench]

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