User contact modal

* adds user/includes/contact_modal_button.html for calling contact data of a user
* adds user contact modal to intervention detail view
* adds translations

user/templates/user/includes/contact_modal_button.html

@@ -0,0 +1,6 @@
+{% load fontawesome_5 i18n %}
+
+<button class="btn btn-default btn-modal" data-form-url="{% url 'user:contact' user.id %}" title="{% trans 'Show contact data' %}">
+    {% fa5_icon 'id-card' %}
+    <span>{{user.username}}</span>
+</button>