[#21] Client: Allows multinenant client

Using one client for several owners

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

src/FrostFS.SDK.ClientV2/Parameters/Credentials.cs

@@ -0,0 +1,11 @@
+using FrostFS.SDK.ModelsV2;
+using System.Security.Cryptography;
+
+namespace FrostFS.SDK.ClientV2.Parameters;
+
+public class Credentials(ECDsa key, OwnerId ownerId)
+{
+    public ECDsa Key { get; } = key;
+
+    public OwnerId OwnerId { get; } = ownerId;
+}