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/ModuleContent.cs

@@ -1,9 +1,23 @@
-namespace Oqtane.Models
+namespace Oqtane.Models
 {
+    /// <summary>
+    /// Generic Model for Module-Contents to enable Import/Export of the Module-Data
+    /// </summary>
     public class ModuleContent
     {
+        /// <summary>
+        /// Reference to a <see cref="ModuleDefinition"/> for which this content is relevant. 
+        /// </summary>
         public string ModuleDefinitionName { get; set; }
+
+        /// <summary>
+        /// Version of the <see cref="ModuleDefinition"/> which is used here. _It's not the version of the Content_
+        /// </summary>
         public string Version { get; set; }
+
+        /// <summary>
+        /// Serialized Content of the module for import/export.
+        /// </summary>
         public string Content { get; set; }
     }
 }