Revert "Add a barebones "embedded" mode (bug #1117643)" (bug #1533019)

This reverts commit bdc1a0ee5d65f2e5c8d6173da8e8b83febb6c31f.

Conflicts:
        libravatar/account/urls.py
        libravatar/account/views.py
        libravatar/templates/account/assign_photo_email.html
        libravatar/templates/account/crop_photo.html
        libravatar/templates/account/profile_embedded.html
        libravatar/templates/account/upload_photo.html
        libravatar/templates/base_embedded.html
        static/css/embedded.css