added API Management for managing site level entity permissions

Oqtane.Shared/Models/Api.cs

@@ -0,0 +1,23 @@
+namespace Oqtane.Models
+{
+    /// <summary>
+    /// API management 
+    /// </summary>
+    public class Api
+    {
+        /// <summary>
+        /// Reference to a <see cref="Site"/> 
+        /// </summary>
+        public int SiteId { get; set; }
+
+        /// <summary>
+        /// The Entity Name
+        /// </summary>
+        public string EntityName { get; set; }
+
+        /// <summary>
+        /// The permissions for the entity
+        /// </summary>
+        public string Permissions { get; set; }
+    }
+}