support custom master url

refactor api instatation to allow custom master url in config

SharedLibraryCore/Interfaces/IMasterCommunication.cs

@@ -0,0 +1,24 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace SharedLibraryCore.Interfaces
+{
+    /// <summary>
+    /// defines the capabilities of the communication to the master server
+    /// </summary>
+    public interface IMasterCommunication
+    {
+        /// <summary>
+        /// checks the current version of IW4MAdmin against the master version
+        /// </summary>
+        /// <returns></returns>
+        Task CheckVersion();
+
+        /// <summary>
+        /// Sends heart beats to the master
+        /// </summary>
+        /// <param name="token">Cancellation token</param>
+        /// <returns></returns>
+        Task RunUploadStatus(CancellationToken token);
+    }
+}