Modularized database information, updated iqtree and fastme modules

[itrujnara]

PR checklist

• Database information is now processed in a fully modular way, allowing anyone to easily integrate new fetching modules without changing any existing ones. New versions of iqtree and fastme that use the meta map have been added, and code has been updated to match.
• If you've fixed a bug or added code that should be tested, add tests! We get there when we get there.
• Make sure your code lints (nf-core lint).
• Ensure the test suite passes (nextflow run . -profile 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).
  Note: There is no documentation at all so nothing to update.

[luisas]

LGTM :)