feat(core): defer external scripts

Set defer attribute on script tags for external
scripts.

apis_core/core/templates/base.html

@@ -58,20 +58,26 @@
  {% endblock styles %}
 
  {% block scriptHeader %}
- <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
+ <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"
+ defer></script>
  {# Bootstrap 4.6.2 bundle (without jQuery) #}
  {# see https://getbootstrap.com/docs/4.6/getting-started/introduction/ #}
  <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js"
  integrity="sha384-Fy6S3B9q64WdZWQUiU+q4/2Lc9npb8tCaSX9FK7E8HnRr0Jz8D6OP9dO5Vg3Q9ct"
- crossorigin="anonymous"></script>
- <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/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>
+ crossorigin="anonymous"
+ defer></script>
+ <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/js/bootstrap-multiselect.min.js"
+ defer></script>
+ <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.3.4/leaflet.js"
+ defer></script>
+ <script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.5/js/select2.full.min.js"
+ defer></script>
  <script src="https://unpkg.com/[email protected]"
  integrity="sha384-D1Kt99CQMDuVetoL1lrYwg5t+9QdHe7NLX/SoJYkXDFfX37iInKRy5xLSi8nO7UC"
- crossorigin="anonymous"></script>
- <script src="{% static "js/core.js" %}"></script>
- <script src="{% static 'js/E53_Place_popover.js' %}"></script>
+ crossorigin="anonymous"
+ defer></script>
+ <script src="{% static "js/core.js" %}" defer></script>
+ <script src="{% static 'js/E53_Place_popover.js' %}" defer></script>
  {% endblock %}
 
  </head>