New List option when adding a book #149
Description
Right now when a user is adding a book and choosing a list on which to include the the book, only the existing lists are options. There should be a "+ New List" option in the dropdown. This option should appear at the top of the list with a divider separating this option from the other options that are already viable lists.
When the "+ New List" is clicked, it should open a modal. This modal should contain the form that already exists in the /add-list page. Make this form a reusable component. When the user adds a list from the Add Book page, it should close this modal with the "Add List" form, and include the new list in the dropdown as a viable option to include the new book on.