Optimize the url alias batchUpdate

[idimopoulos]

\Drupal\rdf_entity\Plugin\pathauto\AliasType\RdfEntityAliasType::batchUpdate is built according to the parent ::batchUpdate method. However, there is an issue with this approach as it might miss some orphaned cases.
The parent method creates a joined query where both aliases and entities are in the same result. Since this is not possible with rdf entity, we should probably not follow the same approach.
As discussed today with Sander and Francesco, we will load the complete list of rdf entities and store it in the context while checking the array so that we can easily create diffs and intersects to derive which entities need update.

This will also fix the issue that we are currently facing with the number of ids that exist in the site. We cannot request entities that have an alias already because the number of entities are a few thousands and concatenating 4k uris in an http request probably hits a limit.