Implement AuthService and ApiClient core logic

Models/FileUploadModels.cs

@@ -0,0 +1,20 @@
+using Newtonsoft.Json;
+using System.Collections.Generic;
+
+namespace Chtn.CSharp.SDK.Models.Media
+{
+    public class RegisterUploadReq
+    {
+        [JsonProperty("roomId")] public string RoomId { get; set; }
+        [JsonProperty("userid")] public string UserId { get; set; }
+        [JsonProperty("files")] public List<FileUploadRegistration> Files { get; set; }
+    }
+    public class FileUploadRegistration
+    {
+        [JsonProperty("size")] public long Size { get; set; }
+        [JsonProperty("type")] public string Type { get; set; }
+        [JsonProperty("name")] public string Name { get; set; }
+        [JsonProperty("fileId")] public string FileId { get; set; }
+    }
+    public class RegisterUploadResp { public string UploadId { get; set; } }
+}