Removed the pimcore/admin-ui-classic-bundle dependency. The bundle no longer implements
PimcoreBundleAdminClassicInterface and no longer uses BundleAdminClassicTrait.
Removed all ExtJS-based JavaScript and CSS paths. getCssPaths() and getJsPaths() were removed from
PimcoreDataImporterBundle.
PimcoreAdminBundle is no longer registered as a dependent bundle.
The configuration panel is now implemented in Pimcore Studio.
Pimcore\Bundle\AdminBundle\Helper\QueryParams is no longer used. It was replaced by
DataTypeServiceInterface::extractSortingSettings().
The messenger transport DSN is configurable via the %pimcore.messenger.transport_dsn_prefix% container parameter
instead of being hardcoded to doctrine://default. The installer can now wire the transport DSN from environment
variables such as PIMCORE_MESSENGER_TRANSPORT_DSN_PREFIX.