[Patch] fixed the invitations logic

public/css/style.css

src/Controller/HomeController.php

src/Controller/InvitationController.php

src/Controller/UserController.php

src/Controller/WishlistController.php

src/Entity/Invitation.php

src/Entity/User.php

src/Entity/Wishlist.php

templates/invitation/edit.html.twig

templates/invitation/index.html.twig

templates/invitation/show.html.twig

templates/wishlist/index.html.twig

templates/wishlist/new.html.twig