Add multisearch with probability of overlap calculation

[olgabot]

Use the probability of overlap calculation provided in sourmash-bio/sourmash_plugin_branchwater#458 to compute statistical significance of search results from all-by-all comparisons.

• Add multisearch module
• Increas split size for split2 so it doesn't run
• Create search subworkflow
• Add search workflow import
• Add versions of search output

PR checklist

• 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 pipeline conventions in the contribution docs
• If necessary, also make a PR on the nf-core/kmerseek branch on the nf-core/test-datasets repository.
• Make sure your code lints (nf-core lint).
• Ensure the test suite passes (nextflow run . -profile test,docker --outdir <OUTDIR>).
• Check for unexpected warnings in debug mode (nextflow run . -profile debug,test,docker --outdir <OUTDIR>).
• Usage Documentation in docs/usage.md is updated.
• Output Documentation in docs/output.md is updated.
• CHANGELOG.md is updated.
• README.md is updated (including new tool citations and authors/contributors).

[notion-workspace]

Add multisearch with search significance to kmerseek

[olgabot]

Filed a bug #8 re needing to update to the template in a separate PR.

[olgabot]

Merging and ignoring the linting issues for now