Broke out the table column templates into individual template files

templates/tables/columns/activities-user.html.twig

@@ -0,0 +1,17 @@
+<script id="{{table.id}}-column-user" type="text/x-handlebars-template">
+    {% verbatim %}
+    <td data-text="{{row.user.last_name}}">
+        {{#if row.user }}
+            <strong>
+                <a href="{{site.uri.public}}/users/u/{{row.user.user_name}}">{{row.user.first_name}} {{row.user.last_name}} ({{row.user.user_name}})</a>
+            </strong>
+            <div class="js-copy-container">
+                <span class="js-copy-target">{{row.user.email}}</span>
+                <button class="btn btn-xs uf-copy-trigger js-copy-trigger"><i class="fas fa-copy"></i></button>
+            </div>
+        {{ else }}
+            <i>{% endverbatim %}{{translate("USER.DELETED")}}{% verbatim %}</i>
+        {{/if }}
+    </td>
+    {% endverbatim %}
+</script>