Add a configurePersistentParameters method

[VincentLanglet]

Subject

This allow to declare getPersistentParameters as final.

This prevents the developer to override incorrectly the method and loosing the benefit of the extensions.
For instance, if you look at the doc I updated, the override was losing the code.

        foreach ($this->getExtensions() as $extension) {
                $params = $extension->getPersistentParameters($this);

                // NEXT_MAJOR: Remove this check, since return typehint is added
                if (!\is_array($params)) {
                    throw new \RuntimeException(sprintf(
                        'The %s::getPersistentParameters must return an array',
                        \get_class($extension)
                    ));
                }

                $parameters = array_merge($parameters, $params);
        }

Plus it add consistency: You want to override somethings ? Use the protected method configure*.

Changelog

### Added
- `AbstractAdmin::configurePersistentParameters()`
- `AdminExtensionInterface::configurePersistentParameters()`

### Deprecated
- Overriding `AbstractAdmin::getPersistentParameters()`
- `AdminExtensionInterface::getPersistentParameters()`

[core23]

This causes some deprecation warnings, because the AbstractAdminExtension does not provide this method @VincentLanglet