Reorgranised blade view files to form a convention

- Primarily moved and re-organised view files.
- Included readme within views to document the convention.
- Fixed some issues with page field select list in previous commit.
- Tweaked some route names while going through.
- Split some views out further.

Closes #2805

app/Http/Controllers/BookSortController.php

@@ -43,7 +43,7 @@ class BookSortController extends Controller
         $book = $this->bookRepo->getBySlug($bookSlug);
         $bookChildren = (new BookContents($book))->getTree();
 
-        return view('books.sort-box', ['book' => $book, 'bookChildren' => $bookChildren]);
+        return view('books.parts.sort-box', ['book' => $book, 'bookChildren' => $bookChildren]);
     }
 
     /**