misc: move Models & Helpers into Common & Avalonia projects

src/Ryujinx/Common/Models/Github/GithubReleasesJsonResponse.cs

@@ -0,0 +1,12 @@
+using System.Collections.Generic;
+
+namespace Ryujinx.Ava.Common.Models.Github
+{
+    public class GithubReleasesJsonResponse
+    {
+        public string Name { get; set; }
+        
+        public string TagName { get; set; }
+        public List<GithubReleaseAssetJsonResponse> Assets { get; set; }
+    }
+}