Add distinction between people and things in elections

One should also be able to add elections for things e.g. yes/no which should not be displayed as people. We can then reactivate displaying avatars in elections with people. index.html in vote:

{% if application.avatar %}
   <img src="{{ application.avatar.url }}" class="applicant-picture" alt="applicant-picture">
   {#                    {% else %}#}
   {#                      <img src="{% static 'img/blank_avatar.png' %}" class="applicant-picture"#}
   {#                           alt="applicant-picture">#}
{% endif %}