Rename 'update.manager' service and related code

Drupal\update\UpdateManagerInterface is a pain, and UpdateManagerInterface::NOT_SECURE and friends are sprinkled throughout.

This might be more trouble than it's worth. From a Slack thread today:
https://drupal.slack.com/archives/C079NQPQUEN/p1745370644226489

dww: It's not totally clear to me why this is even a service.
larowlan: We have a moved class autoloader in core now, search for - you can define a container param with modulename.moved_classes that will load the new name - see core.moved_classes in core.services.yml for an example
larowlan: You can also add deprecated to service definitions - see library.discovery.collector in core.services.yml
so I think they should handle the service name and the class names - i.e. I think we have the tools for this now
dww: Thanks for those details!
dww: Stepping back a bit -- is this even worth it?
dww: Maybe "no one" cares that this service / interface have this name, even if it doesn't really "manage" anything?
larowlan: :shrug: naming is hard
larowlan: Maybe something to ask the UX team - package manager is working to rename 'Stage' to 'Sandbox' in class names out of feedback from the UX team even though its really only DX
moshe: i vote for not worth it

I understand the update.manager service sound like a problem as it exists in the global namespace, but do the classes under update module really pose that much of a problem?

The classes in the summary implement the update.manager service.

Also, the constants in UpdateManager are sprinkled throughout the code. Could make an enum out of them, and deprecate the constants.

I agree that not having anything in update module that is called update manager would be best, but there is some effort vs benefit review needed here :) The service name in the global namespace is indeed highly confusing once there is another module called update manager in core.

Indeed, see #2:

This might be more trouble than it's worth.

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dww: Stepping back a bit -- is this even worth it?

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I opened this issue precisely to discuss the cost / benefit. 😅