Broke out the table column templates into individual template files

templates/tables/activities.html.twig

@@ -0,0 +1,44 @@
+{# This partial template renders a table of user activities, to be populated with rows via an AJAX request.
+ # This extends a generic template for paginated tables.
+ #
+ # Note that this template contains a "skeleton" table with an empty table body, and then a block of Handlebars templates which are used
+ # to render the table cells with the data from the AJAX request.
+#}
+
+{% extends "tables/table-paginated.html.twig" %}
+
+{% block table %}
+    <table id="{{table.id}}" class="tablesorter table table-bordered table-hover table-striped" data-sortlist="[[0, 1]]">
+        <thead>
+            <tr>
+                <th class="sorter-metanum" data-column-name="occurred_at" data-column-template="#{{table.id}}-column-occurred-at" data-priority="1">{{translate('ACTIVITY.TIME')}} <i class="fas fa-sort"></i></th>
+                {% if 'user' in table.columns %}
+                    <th class="sorter-metatext" data-column-name="user" data-column-template="#{{table.id}}-column-user" data-priority="1">{{translate('USER')}} <i class="fas fa-sort"></i></th>
+                {% endif %}
+                <th class="sorter-metatext" data-column-name="description" data-column-template="#{{table.id}}-column-description" data-priority="1">{{translate("DESCRIPTION")}} <i class="fas fa-sort"></i></th>
+            </tr>
+        </thead>
+        <tbody>
+        </tbody>
+    </table>
+{% endblock %}
+
+{% block table_cell_templates %}
+    {# This contains a series of <script> blocks, each of which is a client-side Handlebars template.
+     # Note that these are NOT Twig templates, although the syntax is similar.  We wrap them in the `verbatim` tag,
+     # so that Twig will output them directly into the DOM instead of trying to treat them like Twig templates.
+     #
+     # These templates require handlebars-helpers.js, moment.js
+    #}
+    {% block table_activities_column_occurred_at %}
+        {% include "tables/columns/activities-occurred_at.html.twig" %}
+    {% endblock %}
+
+    {% block table_activities_column_user %}
+        {% include "tables/columns/activities-user.html.twig" %}
+    {% endblock %}
+
+    {% block table_activities_column_description %}
+        {% include "tables/columns/activities-description.html.twig" %}
+    {% endblock %}
+{% endblock %}