Replace module procedural functions with a service

I spent an awfully long time cleaning up typing errors and phpcs errors and cspell notices and phpstan errors, but most of those were inherited from the old procedural function definitions. And, since there are no tests for this module still, the only thing we have to go on is these code quality checks.

There are a few phpcs notices left - these are missing parameter descriptions which were also missing from the procedural functions in the .module. While I added a whole lot of parameter descriptions, there were a few I wasn't sure about without doing a lot more research, so I left those blank. They can be cleaned up in another issue.

TR → changed the visibility of the branch 2.0.x to hidden.

TR → changed the visibility of the branch 8.x-1.x to hidden.

TR → changed the visibility of the branch 3471716-replace-module-procedural to hidden.

Created a new MR because it's easy to deal with the changes from 📌 [9.4] All hook invocation delegated to Module Handler service Fixed in a new branch rather than deal with all the merge conflicts in the old branch.

Automatically closed - issue fixed for 2 weeks with no activity.