:sparkles: subworkflow/freebayes_parallel

PR checklist

Closes #19

[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
[ ] If necessary, include test data in your PR.
[x] Remove all TODO statements.
[x] Emit the versions.yml file.
[ ] Follow the naming conventions.
[ ] Follow the parameters requirements.
[ ] 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
- [ ] PROFILE=singularity pytest --tag <MODULE> --symlink --keep-workflow-wd --git-aware
- [ ] PROFILE=conda pytest --tag <MODULE> --symlink --keep-workflow-wd --git-aware