bcbio automated Docker builds

Uses GitHub actions and Quay to build Docker images for bcbio. Automates and splits up the monolithic bcbio/bcbio Docker container.

Docker images

This builds a variety of Docker images, supporting runs using bcbio generated CWL:

• bcbio-base -- A base version of bcbio containing the code and no tools. This is the building block for application specific containers.
• bcbio-vc -- bcbio with tools for variant calling: alignment; quality control; SNP, indel and structural variant callers
• bcbio-rnaseq -- bcbio with tools for RNA-seq analysis: trimming, alignment quantitation and quality control.

The YAML files defining tools installed in the target Docker images are in packages. We autogenerate these from tool requirements in CWL specification files.