Add support for IsPublic to all Setting types, enable Url Mapping for internal links

Oqtane.Client/Services/Interfaces/IUrlMappingService.cs

@@ -24,6 +24,14 @@ namespace Oqtane.Services
         /// <returns></returns>
         Task<UrlMapping> GetUrlMappingAsync(int urlMappingId);
 
+        /// <summary>
+        /// Get one specific <see cref="UrlMapping"/>
+        /// </summary>
+        /// <param name="siteId">ID-reference of a <see cref="Site"/></param>
+        /// <param name="url">A url</param>
+        /// <returns></returns>
+        Task<UrlMapping> GetUrlMappingAsync(int siteId, string url);
+
         /// <summary>
         /// Add / save a new <see cref="UrlMapping"/> to the database.
         /// </summary>