Add Steam auth, platform validators & name gen

RecNet.Application/Common/PlatformAuth/PlatformAuthResult.cs

@@ -0,0 +1,21 @@
+namespace RecNet.Application.Common.PlatformAuth;
+
+public class PlatformAuthResult
+{
+    public bool Succeeded { get; private set; }
+    public string? Message { get; private set; }
+    public string? Name { get; private set; }
+    
+    private PlatformAuthResult(bool succeeded, string? message, string? name)
+    {
+        Succeeded = succeeded;
+        Message = message;
+        Name = name;
+    }
+    
+    public static PlatformAuthResult Success(string? name)
+        => new(true, null, name);
+
+    public static PlatformAuthResult Failure(string? message = null)
+        => new(false, message, null);
+}