implement client and server service implementations in Html/Text module

Oqtane.Shared/Interfaces/IServerService.cs

@@ -0,0 +1,9 @@
+namespace Oqtane.Modules
+{
+    /// <summary>
+    /// Empty interface used to decorate server module services for auto registration as scoped
+    /// </summary>
+    public interface IServerService
+    {
+    }
+}