feat: add request to log in

ApiDto/Requests/LoginRequest.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Requests;
+
+/// <summary>
+/// Request to receive protected content
+/// </summary>
+public class LoginRequest
+{
+    /// <summary>
+    /// Login or Email to identify the client.
+    /// </summary>
+    [Required]
+    public required string Username { get; set; }
+
+    /// <summary>
+    /// The client's password.
+    /// </summary>
+    [Required]
+    public required string Password { get; set; }
+}