Surface a button for "duplicate trip"

I recently implemented this functionality, but kept the URL hidden &
otherwise undocumented. I was hoping to totally refactor
`trip_edit_buttons` so that more code lives in Python (where it can be
typechecked and otherwise more robustly tested). However, this is
hopefully a step in that direction.

Author: DavidCain

ws/templates/for_templatetags/trip_edit_buttons.html

@@ -1,17 +1,5 @@
-{% if is_chair or is_creator or is_trip_leader %}
-  {# Show label that describes all available functions #}
-  <h4>
-    {% if is_chair %}
-      Activity chair
-    {% elif is_creator %}
-      Creator
-    {% elif is_trip_leader %}
-      Leader
-    {% endif %}
-    functions
-  </h4>
-
-  <div class="btn-group" role="group">
+<div class="btn-group" role="group">
+  {% if is_chair or is_creator or is_trip_leader %}
     <a type="button" class="btn btn-default" href="{% url 'edit_trip' trip.pk %}"   ><i class="fas fa-edit"  ></i>&nbsp;Edit</a>
     <a type="button" class="btn btn-default" href="{% url 'trip_medical' trip.pk %}"><i class="fas fa-medkit"></i>&nbsp;WIMP info</a>
 
@@ -51,10 +39,11 @@ <h4>
         </button>
       {% endif %}
     {% endif %}
-  </div>
-
-  {% if is_creator or is_chair %} {# Other trip leaders cannot delete the trip #}
-    <data-delete class="pull-right" data-api-slug="trips" data-obj-id="{{ trip.pk }}"></data-delete>
   {% endif %}
 
+  <a type="button" class="btn btn-default" href="{% url 'create_trip' %}?duplicate_trip_id={{ trip.pk }}"><i class="fas fa-copy"  ></i>&nbsp;Duplicate</a>
+</div>
+
+{% if is_creator or is_chair %} {# Other trip leaders cannot delete the trip #}
+  <data-delete class="pull-right" data-api-slug="trips" data-obj-id="{{ trip.pk }}"></data-delete>
 {% endif %}

ws/templates/trips/view.html

@@ -13,9 +13,7 @@
 {% endif %}
 
 {% if can_admin or viewing_participant.is_leader %}
-  {% if can_admin %}
-    {% trip_edit_buttons trip viewing_participant user %}
-  {% endif %}
+  {% trip_edit_buttons trip viewing_participant user %}
 
   <div data-ng-controller="tripTabManager">
     <uib-tabset id="admin-trip-tabs">