[Authentication] Add required attributes for login dbo

Authentication/Authentication.csproj

       <HintPath>..\packages\Newtonsoft.Json.6.0.8\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
     <Reference Include="System" />
+    <Reference Include="System.ComponentModel.DataAnnotations" />
     <Reference Include="System.Configuration" />
     <Reference Include="System.Core" />
     <Reference Include="System.IdentityModel" />

Authentication/DBO/BasicUserLogin.cs

-namespace iiie.Authentication.DBO
+using System.ComponentModel.DataAnnotations;
+
+namespace iiie.Authentication.DBO
 {
     public class BasicUserLogin
     {
+        [Required]
+        [MinLength(1)]
         public string Username { get; set; }
 
+        [Required]
+        [MinLength(1)]
         public string Password { get; set; }
     }
 }