enhanced plugin support (#634)

- refactored admin controller and templates
- plugin support for entity actions
- changed column mail to email in customer table
- refactored theme events

templates/user/delete.html.twig

@@ -0,0 +1,22 @@
+{% extends 'base.html.twig' %}
+{% import "macros/widgets.html.twig" as widgets %}
+{% import "macros/datatables.html.twig" as tables %}
+
+{% block page_title %}{{ 'admin_user.title'|trans }}{% endblock %}
+{% block page_subtitle %}{{ 'admin_user.subtitle'|trans }}{% endblock %}
+
+{% block main %}
+
+    {% set params = {
+        '%user%': '<strong>' ~ widgets.username(user) ~ '</strong>',
+        '%records%': '<strong>' ~ stats.recordsTotal ~ '</strong>',
+        '%duration%': '<strong>' ~ stats.durationTotal|duration ~ '</strong>'
+    } %}
+
+    {{ include('default/_form_delete.html.twig', {
+        'message': "admin_user.delete_confirm"|trans(params)|raw,
+        'form': form,
+        'back': path('admin_activity')
+    }) }}
+
+{% endblock %}