[Regulatory] Write down security aspects of using nf-core pipelines

[apeltzer]

Should write down some aspects on potential impllications that running nf-core pipelines could have, this includes.

• Container security scanning (CVE handling, patching etc pp) - what is done on nf-core level vs what is on the user / institution running nf-core pipelines
• Safeguards for code scanning - entering malicious code into nf-core pipelines: Guidelines, documentation, reivew and testing schemes for modules