updated reference paths and UMI param names in test_full.config

[iraiosub]

Changes to test_full config so running the pipeline with -profile test_full runs beyond UMI deduplication:

• updated FASTA and GTF paths to those hosted on Ensembl instead of igenomes. These are downloaded at runtime (tested).
• renamed UMI related params to match those in nextflow.config and enabled UMI extraction (so now UMI collapse doesn't fail)
• despite these changes that help the test_full progress further, test_full still fails in later steps at processes related to consensus peak analyses

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 - add to the software_versions process and a regex to scrape_software_versions.py
  • 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/clipseq 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).
• 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).

[iraiosub]

closing this PR, as these changes are also implemented in #166