Remove multiple_sep

[emmarousseau]

Description

• Removing "multiple_sep" field from config (gffread and samtools_stats)
• Small formatting changes to default fields

Issue ticket number

Partially addresses issue #77

Checklist before requesting a review

• [x] I have performed a self-review of my code

• [x] Conforms to the Contributing guidelines

• [ ] Proposed changes are described in the CHANGELOG.md

• [x] I have tested my code with viash ns test --parallel -q <name or namespace>

• Check the correct box. Does this PR contain:

  • [ ] Breaking changes
  • [ ] New functionality
  • [ ] Major changes
  • [x] Minor changes
  • [ ] Documentation
  • [ ] Bug fixes

[rcannood]

Dang. I forgot to ask you to add something to the changelog. Oh well.