Add modkit pileup

[Michal-Babins]

PR checklist

Closes #3950

• [x ] This comment contains a description of changes (with reason).
• [ x] If you've fixed a bug or added code that should be tested, add tests!
• [ x] If you've added a new tool - have you followed the module conventions in the contribution docs
• [ x] If necessary, include test data in your PR.
• [ x] Remove all TODO statements.
• [ x] Emit the versions.yml file.
• [ x] Follow the naming conventions.
• [ x] Follow the parameters requirements.
• [ x] Follow the input/output options guidelines.
• [x ] Add a resource label
• [x ] 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:
  • [x ] PROFILE=docker pytest --tag <MODULE> --symlink --keep-workflow-wd --git-aware
  • [x ] PROFILE=singularity pytest --tag <MODULE> --symlink --keep-workflow-wd --git-aware
  • [ x] PROFILE=conda pytest --tag <MODULE> --symlink --keep-workflow-wd --git-aware