Rewrite Galaxy container resolver

[innovate-invent]

The Galaxy container resolver currently has quay.io/bioconda hardcoded as the only container source.
This needs to be rewritten to allow additional sources to be configurable via Galaxies container_resolvers_conf.yml

The current implementation also makes direct docker registry v1 http requests to quay.io, this needs to be swapped out for the official docker sdk. This is required to improve forwards compatibility and upgrade to v2 of the docker registry api spec. Currently it is not possible to configure a pull through proxy as the proxy is not compatible with v1 of the spec.