Added a Release Stream Picker

EZPPClient Installer/Utils/ReleaseStreamUtil.cs

@@ -0,0 +1,48 @@
+using ModernWpf.Controls;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace EZPPClient_Installer
+{
+  class ReleaseStreamUtil
+  {
+
+    public static async Task<List<string>> GetAvailableReleaseStreams()
+    {
+
+      List<string> releaseStreamList = new List<string>();
+
+      try
+      {
+        using (WebClient wc = new WebClient())
+        {
+          wc.Headers.Add("user-agent", "EZPPClientInstaller");
+          var data = await wc.DownloadStringTaskAsync("https://new.ez-pp.farm/ezppclient?releases");
+          string[] dataList = data.Split('\n');
+          foreach (string datastring in dataList)
+          {
+            if (string.IsNullOrWhiteSpace(datastring))
+              continue;
+            releaseStreamList.Add(datastring);
+          }
+        }
+      }
+      catch (WebException error)
+      {
+        _ = new ContentDialog()
+        {
+          Title = "Oops...",
+          Content = "A error occurred while trying to fetch the ReleaseStreams.\n" + error.Message,
+          PrimaryButtonText = "Okay"
+        }.ShowAsync();
+      }
+
+      return releaseStreamList;
+    }
+
+  }
+}