Add missing factories

[Ilyes512]

• Add missing factory methods to src/Query/Query.php
• Add missing factory methods to src/Aggregation/Aggregation.php
• Applied code style linter
  • I did re-enable use_nullable_type_declaration that is set to off by the symfony rule set. It would other wise remove null from parameter type hint when the default value was set to null.
• Fixed a minor type I came across in a comment
• Fixed 2 deprecations warnings in tests
• Fixed 2 assertions in tests