[#190] Add PlacementPolicy dataclass

Allow to parametrize tests with placement policy.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

src/frostfs_testlib/storage/dataclasses/policy.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+
+
+@dataclass
+class PlacementPolicy:
+    name: str
+    value: str
+
+    def __str__(self) -> str:
+        return self.name
+
+    def __repr__(self) -> str:
+        return self.__str__()