ModuleHandler should not maintain list of installed modules now that ModuleExtensionList exists

It looks like we are confusing the %container.modules% container parameter and the @extension.list.module service.
These have very different purposes.

The ModuleExtensionList is _not_ the "canonical repository" for installed modules.
The %container.modules% parameter is, but it is not a service, so it cannot replace what we have in ModuleHandler.

Also it contains arrays instead of Extension objects - which is actually ok, because the Extension objects from ModuleHandler are never fully initialized with all the properties they would have in ModuleExtensionList.

Child issue is fixed 📌 Deprecate ModuleHandlerInterface::getName() Fixed

Needs more work in MR

Re-roll Patch for 11.x.

The Needs Review Queue Bot → tested this issue. It fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

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