Remove quill and upload_image

[marcua]

We don't use them anymore and they likely won't appear in the new frontend

git grep upload_image
orchestra/api_urls.py:from orchestra.views import upload_image
orchestra/api_urls.py:    url(r'^interface/upload_image/$',
orchestra/api_urls.py:        upload_image,
orchestra/api_urls.py:        name='upload_image'),
orchestra/static/dist/main.js:        var uploadAPIEndpoint = '/orchestra/api/interface/upload_image/';
orchestra/static/orchestra/common/components/quill/quill.directive.es6.js:        var uploadAPIEndpoint = '/orchestra/api/interface/upload_image/'
orchestra/views.py:def upload_image(request):