Added a clickable plant image swapper

The Large image on the details page can now be replaced by any of the
thumbnail images. Also, added e2e and unit tests to test the new
feature.
Added Animation

There is one bug. The animation in the main image on the details page is
not working. Also, the click to change image is not working
consistently.
Added images for all the plants

The images have all been resized to 400x400 and the thumbnails have been
resized to 68x68.