Make all docker remotes use first HEAD requests for manifests and BLOBs by default

All docker repositories will now do HEAD <> GET. For manifest it's HEAD <> HEAD <> GET.
This should be default behavior.

To revert back, it is possible to switch on the Bypass HEAD Requests flag in the UI / Advanced.

One exception for this is something called configBlob - this request is going to be using GET <> GET.