Fixe Issues/3735: Check for docker and docker daemon and fail before download

[JulianFlesch]

Closes #3735

Also adds a try...except around the container_fetcher initialization, to fail gracefully but with a meaningful error message.

PR checklist

• This comment contains a description of changes (with reason)
• CHANGELOG.md is updated
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated

[codecov]

Codecov Report

❌ Patch coverage is 46.66667% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.22%. Comparing base (5ec33a0) to head (51d285f).

Files with missing lines	Patch %	Lines
nf_core/pipelines/download/download.py	33.33%	6 Missing ⚠️
nf_core/pipelines/download/docker.py	66.66%	2 Missing ⚠️

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.