Auto-ignore modules from being updated with nf-core modules install --all

[drpatelh]

Support for ignoring modules with nf-core modules bump-versions was added in #1162 but it would also be good to have the ability to use .nf-core.yml to ignore modules from being updated when running nf-core modules install --all for scenarios where the pipeline developer may want to use an older version of a module available on nf-core/modules and stick to that. This would save having to manually update a subset of modules each time an update is required.

[ErikDanielsson]

Implemented as of the merge of #1206