Add redirect method and custom 404 error handling

[javad-zobeidi]

1. Add redirect method ([Feature Request] - Add redirect method for redirecting to a specific location #144):

   • A new redirect method is added to the Response class to simplify HTTP redirections.

2. Add custom 404 error handling via HTML file ([Feature Request] - How can I manage the 404 route? #145):

   • Custom handling for 404 errors is implemented, serving a user-defined HTML page when a page is not found, enhancing the error-handling experience.
   • To enable this feature, create an errors directory in the root of the project.
   • Inside the errors directory, create a 404.html file at errors/404.html.
   • This approach enhances the error-handling experience, providing a more user-friendly response for missing pages.

Errors directory placement:

- lib
- errors
    --- 404.html