Plugin to view .nextflow.log files using toolong

[ewels]

⚠️ Relies on Textualize/toolong#47
(Ok technically it builds from my forked dev branch of the above, but it shouldn't do long term)

Could do with some refinement. Specifically:

• Don't just nuke all toolong functionality, only switch on when we think we see Nextflow logs
• Figure out weird behaviour with error / warning / debug blocks (probably some async behaviour?)
• Create command alias, eg. nf-core log or similar.
• Write docs

Testing: pip install this PR and try nf-core log in a directory where you've run Nextflow.