Split the two models into separate container images

[ArtemSokolov]

Users are unlikely to need both models at the same time. Splitting them into separate containers images can help keep the module size smaller.

• Modify the Dockerfile to accept a single model as an argument
• Modify the dockerhub.yml GHA to build two parallel container images: labsyspharm/unmicst:${{ github.event.release.tag_name }} and labsyspharm/unmicst:${{ github.event.release.tag_name }}-duo, passing nucleiDAPI1-5 and nucleiDAPILAMIN as arguments respectively.