[#11] Add Network Snapshot

Signed-off-by: Pavel Gross <p.gross@yadro.com>

src/FrostFS.SDK.ClientV2/Mappers/Netmap/PlacementPolicy.cs

@@ -0,0 +1,32 @@
+using System.Linq;
+using FrostFS.Netmap;
+
+namespace FrostFS.SDK.ClientV2.Mappers.GRPC.Netmap;
+
+public static class PlacementPolicyMapper
+{
+    public static PlacementPolicy ToGrpcMessage(this ModelsV2.Netmap.PlacementPolicy placementPolicy)
+    {
+        var pp = new PlacementPolicy
+        {
+            Filters = { },
+            Selectors = { },
+            Replicas = { },
+            Unique = placementPolicy.Unique
+        };
+        foreach (var replica in placementPolicy.Replicas)
+        {
+            pp.Replicas.Add(replica.ToGrpcMessage());
+        }
+
+        return pp;
+    }
+
+    public static ModelsV2.Netmap.PlacementPolicy ToModel(this PlacementPolicy placementPolicy)
+    {
+        return new ModelsV2.Netmap.PlacementPolicy(
+            placementPolicy.Unique,
+            placementPolicy.Replicas.Select(replica => replica.ToModel()).ToArray()
+        );
+    }
+}