3598572-d12-annotation-plugins-removal

Removed Annotations Plugins and their fallbacks references in the Plugins Managers definition (as Attributes plugins are supported since Drupal Core 10.2, and the module supports Drupal Core 10.3 +)

GeofieldBackendPluginInterface.php replaced Drupal\geofield\Annotation\GeofieldBackend with Drupal\geofield\Attribute\GeofieldBackend

Kernel/PluginDiscoveryTest.php: removed Annotations mentions Agents.md: replaced annotated plugins with attributes