Adjust to propper dependency injection

Are you sure that's on 1.0.x branch?
In any case, if there is some code that can be converted, pls go ahead, but if it's on 0.2.x - no point.

Added dependency injections where ever found direct drupal calls.

1. Automated tests must pass.
2. There must be no major code quality warnings like this one (possibly fixing those will make the tests pass at the same time).

I have made some more changes to it.

Pls don't set to "needs review" if tests still fail.

Did some clean-up here, various things were causing the test failures:

- it's not necessary to inject the messenger service into forms, you can use $this->messenger() from MessengerTrait

- various constructors weren't calling the parent constructor (and create/createInstance methods similarly weren't passing the right arguments).

- remove unnecessary constructor documentation

- reverts the places using $this in static methods which isn't possible

Tests should be back to green now.

This gets us down from 26 to 21 phpstan errors.

Reviewed & merged, thank you all!