Container Base Url support when creating new modules

[apeltzer]

Description of feature

nf-core/modules#2291 outlines how we will restructure to use params.container_registry for docker containers in the future, e.g. to allow using container mirrors from ECR or potentially other sources.

This means however, that we will have to adjust tools code to query the biocontainers API and split the URL
to use the params.container_registry placeholder. Otherwise users might create new modules using nf-core tooling and have full URLs to quay.io in their newly created module code, which is a bit inconvient. Potentially could also lint for this.

x-ref: nf-core/modules#2291 (comment)

[ewels]

Now using docker registry setting, so this can be closed.