enhancing the function of is_module_installed to be faster

[mFlayyan]

Current behavior before PR:
is_module_installed goes through all modules and look to their state to create a list of all modules that have state=Active then looks for module_name in that list

Desired behavior after PR is merged:
is_module_installed checks if module_name is in registry._init_module set so it takes less time

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[hbrunn]

note to fellow reviewers: This will speed up the backend because for every request, this function is called repeatedly, and will cause tens of extra database requests. Given we really only care about modules actually loaded (as opposed to modules supposed to be installed, but maybe not loaded due to some misconfiguration), I think this is fine

[bealdav]

👍

[dreispt]

Shouldn't there be an upstream PR?

[pedrobaeza]

I think so