Edited views.py: Added class AuthorUpdateView, Edited urls.py: Added path('authors/<int:pk>/edit/), Created editor-author.html

Edited views.py: Added BooksUpdateView, Edited urls.py: added path('books/<int:pk>/edit/, Created edit-book.html

Edited urls.py: Added CreateView, Edited views.py: Added s to book, Edited views.py: Added class AuthorCreateView

Edited books.html, book_details.html, authors.html, authors_details.html: added spaces for clean code

Created html files: books.html, book_details.html, authors.html, author_details.html and Updated models.py