Added local RAG (#756)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Settings/IExternalDataSource.cs

@@ -1,9 +1,16 @@
 using System.Text.Json.Serialization;
 
+using AIStudio.Settings.DataModel;
+
 namespace AIStudio.Settings;
 
 public interface IExternalDataSource : IDataSource, ISecretId
 {
+    /// <summary>
+    /// Which data security policy is applied to this external data source?
+    /// </summary>
+    public DataSourceSecurity SecurityPolicy { get; init; }
+
     #region Implementation of ISecretId
 
     [JsonIgnore]