Add PasswordGeneratorInterface based service. Remove hook_password

The DefaultPasswordGenerator/PasswordGeneratorInterface were only introduced in D9.1.

To do this will require once again updating core_version_requirement beyond 8.9.

The plan will need to be upgraded to segregate 2.0.x from 8.x-1.x completely again.

Attempting to use config settings during GenpassServiceProvider proved fruitless and randomly likely to fail. This module will now by default replace core's password_generator service, but using the option, only use genpass when configured to do so and otherwise calling core DefaultPasswordGenerator.

Combine it with 📌 Tidy up Settings UI Fixed for full effect - attached as patch.

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