PR checklist

Closes #8441

• This comment contains a description of changes (with reason).
• If you've fixed a bug or added code that should be tested, add tests!
• If you've added a new tool - have you followed the module conventions in the contribution docs
• If necessary, include test data in your PR.
• Remove all TODO statements.
• Emit the versions.yml file.
• Follow the naming conventions.
• Follow the parameters requirements.
• Follow the input/output options guidelines.
• Add a resource label
• Use BioConda and BioContainers if possible to fulfil software requirements.
• Ensure that the test works with either Docker / Singularity. Conda CI tests can be quite flaky:
  • For modules:
    • nf-core modules test <MODULE> --profile docker
    • nf-core modules test <MODULE> --profile singularity
    • nf-core modules test <MODULE> --profile conda
  • For subworkflows:
    • nf-core subworkflows test <SUBWORKFLOW> --profile docker
    • nf-core subworkflows test <SUBWORKFLOW> --profile singularity
    • nf-core subworkflows test <SUBWORKFLOW> --profile conda

This PR adds the preparesegmentation process for cell segmentation using the vizgen-postprocessing tool for the MERSCOPE spatial omics instrument. The plan would be to add runsegmentationontile​ and compiletilesegmentation​ as subsequent modules to create a segmentation subworkflow for the tool.

The test data is prepared within the test module, using generated dummy data plus an existing segmentation image in nf-core/test-datasets, which needs to be renamed and put in an images directory to work with this module.

I could not find a BioContainer or BioConda package for this tool.