Add support for .nf-core.yml to nf-core modules update

[ErikDanielsson]

Added support for ignoring modules and specifying module versions in .nf-core.yml when running nf-core modules update at both the module and repository level. A .nf-core.yml can for example be configured in the following way:

lint:
  ...
bump-versions: 
  ...
update: 
  nf-core/modules:
     fastqc: False
     multiqc: True
     untar: "e937c7950af70930d1f34bb961403d9d2aa81c7"
  another-user/modules: False
  yet-another-user/some-repo: "e937c7950af70930d1f34bb961403d9d2aa81c7"

Leaving out a module or a repository has the same effect as settting it to True. The commit SHAs set in .nf-core.yml command has higher precedence than commit SHAs set with--sha`.

Should close #1204.

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

Merging #1206 (62fffff) into dev (6a6c899) will decrease coverage by 0.56%.
The diff coverage is 21.50%.

@@            Coverage Diff             @@
##              dev    #1206      +/-   ##
==========================================
- Coverage   68.86%   68.29%   -0.57%     
==========================================
  Files          50       50              
  Lines        5485     5523      +38     
==========================================
- Hits         3777     3772       -5     
- Misses       1708     1751      +43     

Impacted Files	Coverage Δ
nf_core/modules/modules_repo.py	64.55% <ø> (-0.88%)	⬇️
nf_core/modules/update.py	8.27% <0.00%> (-3.73%)	⬇️
nf_core/modules/install.py	64.10% <50.00%> (+0.57%)	⬆️
nf_core/utils.py	84.46% <50.00%> (-0.18%)	⬇️

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[drpatelh]

Thanks!