cover: tweak styles:

- `optimizeQuality` > `smooth` (CSS language evolution)
- Use `auto` instead of a fixed width.
- Add exceptions for heights and apply them to some previously modified templates.
- Remove `is-large` exception.
- Widen the content column on list curation.

bookwyrm/templates/feed/feed_layout.html

@@ -37,7 +37,7 @@
                                         aria-label="{{ book.title }}"
                                         aria-selected="{% if active_book == book.id|stringformat:'d' %}true{% elif shelf_counter == 1 and forloop.first %}true{% else %}false{% endif %}"
                                         aria-controls="book-{{ book.id }}">
-                                        {% include 'snippets/book_cover.html' with book=book cover_class='is-medium' %}
+                                        {% include 'snippets/book_cover.html' with book=book cover_class='is-h-medium' %}
                                     </a>
                                 </li>
                                 {% endfor %}