Docs: Remove all remaining orphaned images.

...monitoring/performance/img/grafana_dashboard_dropdown.png

doc/monitoring/performance/img/grafana_dashboard_import.png

...ing/performance/img/grafana_data_source_configuration.png

doc/monitoring/performance/img/grafana_data_source_empty.png

doc/monitoring/performance/img/grafana_save_icon.png

...performance/img/metrics_gitlab_configuration_settings.png

doc/topics/autodevops/img/autodevops_domain_variables.png

doc/topics/autodevops/img/guide_connect_cluster.png

doc/topics/autodevops/img/guide_create_cluster.png

doc/topics/autodevops/img/guide_gke_apis_after.png

doc/topics/autodevops/img/guide_gke_apis_before.png

doc/topics/autodevops/img/guide_merge_request_ide.png

...versity/high-availability/aws/img/elastic-file-system.png

doc/user/admin_area/img/license_no_license_message.png

.../settings/img/admin_area_default_artifacts_expiration.png

doc/user/admin_area/settings/img/admin_area_group_edit.png

doc/user/admin_area/settings/img/admin_area_groups.png

...n_area/settings/img/admin_area_maximum_artifacts_size.png

...ea/settings/img/ci_shared_runners_build_minutes_quota.png

doc/user/admin_area/settings/img/group_quota_view.png