feat(core): drop inclusion of select2 javascript and css

We use select2 only in conjunction with django-autocomplete-light,
therefore it doesn't make sense to include it separately.

Closes: #1481

apis_core/core/templates/base.html

@@ -49,8 +49,6 @@
             href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/1.1.2/css/bootstrap-multiselect.css" />
       <link rel="stylesheet"
             href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.3.4/leaflet.css" />
-      <link rel="stylesheet"
-            href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.5/css/select2.min.css" />
       <link rel="stylesheet"
             href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css"
             integrity="sha384-xOolHFLEh07PJGoPkLv1IbcEPTNtaed2xpHsD9ESMhqIYd0nLMwNLD69Npy4HI+N"
@@ -65,7 +63,6 @@
       <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
       <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/1.1.2/js/bootstrap-multiselect.min.js"></script>
       <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.3.4/leaflet.js"></script>
-      <script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.5/js/select2.full.min.js"></script>
       <script src="{% static "js/core.js" %}"></script>
       <script src="{% static 'js/E53_Place_popover.js' %}"></script>
     {% endblock %}