Add full-size test and finer seqdepth grid

[BenjaminWehnert1008]

test_full now runs the GID1A dataset from ENA (PRJEB110196), and the seqdepth rarefaction uses a geometric depth grid instead of 40 even steps.

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/dmscore branch on the nf-core/test-datasets repository.
• Make sure your code lints (nf-core pipelines 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).

[MaximilianStammnitz]

Linked to #68 😇

[BenjaminWehnert1008]

CI now depends on nf-core/test-datasets#1972. Will fail until test datasets got merged.