consider hidden modules when checking for existing dependencies

[boegel]

Currently, only non-hidden modules are considered when checking whether a module for each of the listed dependencies is available. We should also (optionally) consider resolving dependencies with existing hidden modules.
A configuration option --consider-hidden-modules should be added (and disabled by default) to enable this behaviour.

This should make maintaining a module stack that includes hidden modules significantly, by ensuring that a module isn't installed both hidden and non-hidden by accident.

Note that for dependencies which are also listed via hiddendependencies a hidden module must be available; if not, eb will install a hidden module for them. This behaviour should be retained.

cc @stdweird

[stdweird]

as already discussed, i would take one step further and allow the consider-hidden-modules option a list of modules to consider as hidden, similar to the hiddendependencies. then the list of hiddendependencies could be set EB-wide via the configfile instead of defining it in each easyconfig.

[boegel]

On top of this, we can also extend the module naming scheme API to allow for it to flag whether a module should be hidden or not, since that would provide more flexibility, i.e. determine whether installations should be hidden based on more than just the software name.