Add Azure Container Registry helper for docker credentials using hamilton

[simongottschlag]

Hi!

I am currently trying to get cosign to work with Azure Container Registry: sigstore/cosign#1350

It is using the following project to get the token for ACR: https://github.com/chrismellard/docker-credential-acr-env

I would like to include a similar helper in hamilton that will be using hamilton instead of autorest.

[simongottschlag]

As a reference I've started the discussion in go-containerregistry to move them to hamilton and they seem to like the idea: google/go-containerregistry#1263

I think I'll rewrite the PR to not be a helper based on the docker interface but instead be a plain Exchange() function that takes an authorizer.

@manicminer any thoughts or ideas? 😊