More documentation - almost all Models done

https://github.com/oqtane/oqtane.framework/issues/1382
Should not contain any code changes, just docs

Oqtane.Shared/Models/Installation.cs

@@ -1,8 +1,20 @@
-namespace Oqtane.Models
+namespace Oqtane.Models
 {
+    /// <summary>
+    /// Internal message used internally during installation.
+    ///
+    /// Each part of the installation will return the status / message when installing.
+    /// </summary>
     public class Installation 
     {
+        /// <summary>
+        /// Status if everything worked. 
+        /// </summary>
         public bool Success { get; set; }
+
+        /// <summary>
+        /// Message or error in case something failed.
+        /// </summary>
         public string Message { get; set; }
     }
 }