Replace nf-core modules/subworkflows create-test-yaml for nf-test

[adamrtalbot]

Description of feature

Related to #2486 and #2484.

The tools has a good way of automating creating a set of a Pytest and checking md5sums. This is less important with nf-test because of it's support for snaps, but easier tools are always useful. We could replace it with a first run with --generate-snapshot followed by a test to make sure it passes.

[mirpedrol]

Closing as done