Implement object oriented hooks

Worth noting, we found an issue with eca_config_schema_info_alter() not firing when the eca_config module was enabled. I was able to work around this by using an OOP hook.

See 📌 Config validation for ECA models Active

Thanks @michaellander for the additional info. I think, though, that we will not switch to OOP hooks with ECA 2.1 because that version also supports Drupal 10.3 and then things would be broken. We will wait for ECA 3.x which will eventually support ^11.4 || ^12 of Drupal core. Note: 11.4 as the lowest version I've just made up, it's not clear yet which 11 release will be the one that won't see too many breaking changes before Drupal 12.

I've worked on implementing object oriented hooks and the Backwards-compatible Hook implementation for Drupal versions from 10.1 to 11.0 according to https://www.drupal.org/node/3442349 →

Some thoughts:

• When implementing this on one of the next major versions that require at least Drupal 11 then I guess we don't need to consider LegacyHook or any other sort of BC layer. Just going all-in for OOP hooks.
• I didn't look any more in detail, but one thing I noted was that hooks are being registered as listeners into the event_dispatcher service - something ECA does as well. Is it maybe possible that we merge some of our hook-related events entirely to OOP hooks, so we could reduce some class definition overhead?