Users should be able login on WOSCA-book-gallery - hook up login form to API

[mazma1]

This is meant to bring live to the static login form by consuming the sign in API and performing an actual login operation. On successful login, the user should be redirected to a different page that shows that the login works.

For now, it can be a /dashboard route with a dummy page with <div>Dashboard page </div> text, for example.
Also ensure that only authenticated users can access this /dashboard route.

Depends on the signin API