Move shared code to testlib

Signed-off-by: Andrey Berezin <a.berezin@yadro.com>

src/frostfs_testlib/storage/__init__.py

@@ -0,0 +1,33 @@
+from frostfs_testlib.storage.constants import _FrostfsServicesNames
+from frostfs_testlib.storage.dataclasses.frostfs_services import (
+    HTTPGate,
+    InnerRing,
+    MainChain,
+    MorphChain,
+    S3Gate,
+    StorageNode,
+)
+from frostfs_testlib.storage.service_registry import ServiceRegistry
+
+__class_registry = ServiceRegistry()
+
+# Register default public services
+__class_registry.register_service(_FrostfsServicesNames.STORAGE, StorageNode)
+__class_registry.register_service(_FrostfsServicesNames.INNER_RING, InnerRing)
+__class_registry.register_service(_FrostfsServicesNames.MORPH_CHAIN, MorphChain)
+__class_registry.register_service(_FrostfsServicesNames.S3_GATE, S3Gate)
+__class_registry.register_service(_FrostfsServicesNames.HTTP_GATE, HTTPGate)
+# # TODO: Remove this since we are no longer have main chain
+__class_registry.register_service(_FrostfsServicesNames.MAIN_CHAIN, MainChain)
+
+
+def get_service_registry() -> ServiceRegistry:
+    """Returns registry with registered classes related to cluster and cluster nodes.
+
+    ServiceClassRegistry is a singleton instance that can be configured with multiple classes that
+    represents service on the cluster physical node.
+
+    Returns:
+        Singleton ServiceClassRegistry instance.
+    """
+    return __class_registry