Deprecate drupal_check_module() and replace with a service

Searched for drupal_check_module and the 1 instance has been replaced. CR is there. Think this is good.

I'm not sure how useful this is as an API - what about moving the logic to a protected method on the form itself with no replacement? Does any contrib module call this function?

4 usages in contrib http://codcontrib.hank.vps-private.net/search?text=drupal_check_module&f...

There is also very similar/duplicated code for checking run-time requirements in SystemManager::checkRequirements() https://git.drupalcode.org/project/drupal/-/blob/11.x/core/modules/syste...

The page attachments examples from http://codcontrib.hank.vps-private.net/search?text=drupal_check_module&f... look like a bad idea, those modules could directly check their own requirements rather than jump through hoops. mmu is a reasonable example though because it's re-implementing the modules page, but then that's only one or two usages.

The ::getMaxSeverity() method on SystemManager looks identical to the one added here, so we could maybe call that from the form, or move the other helpers into SystemManager? But we definitely shouldn't duplicate that method, so marking needs work.

Hmm. System manager looks like it deals runtime requirements but also with blocks of Menu Links??

Maybe we should expand this to move the runtime requirements checks from SystemManager to the new RequirementsChecker instead?

\Drupal\system\SystemManager::listRequirements() actually calls drupal_load_updates() which depends on ModuleExtensionList as well.

Checking install and runtime requirements seem to be very different. Perhaps we should just move getMaxSeverity() to a utility class instead.

Back to needs review to see if you like this approach.

I've made changes over at 📌 Add value objects to represent the return of hook_requirements Needs review