datetime: Use new setup mechanism

plinth/modules/datetime/__init__.py

@@ -27,21 +27,36 @@ from plinth import cfg
 from plinth import service as service_module
 
 
+version = 1
+
+is_essential = True
+
 depends = ['system']
 
+title = _('Date & Time')
+
+description = [
+    _('Network time server is a program that maintians the system time '
+      'in synchronization with servers on the Internet.')
+]
+
 service = None
 
 
 def init():
     """Intialize the date/time module."""
     menu = cfg.main_menu.get('system:index')
-    menu.add_urlname(_('Date & Time'), 'glyphicon-time',
-                     'datetime:index', 900)
+    menu.add_urlname(title, 'glyphicon-time', 'datetime:index', 900)
 
     global service
     service = service_module.Service(
-        'ntp', _('Network Time Server'),
-        is_external=False, enabled=is_enabled())
+        'ntp', title, is_external=False, enabled=is_enabled())
+
+
+def setup(helper, old_version=None):
+    """Install and configure the module."""
+    helper.install(['ntp'])
+    helper.call('post', service.notify_enabled, None, True)
 
 
 def is_enabled():

plinth/modules/datetime/templates/datetime.html

@@ -1,4 +1,4 @@
-{% extends "base.html" %}
+{% extends "app.html" %}
 {% comment %}
 #
 # This file is part of Plinth.
@@ -21,16 +21,7 @@
 {% load bootstrap %}
 {% load i18n %}
 
-{% block content %}
-
-  <h2>{% trans "Date & Time" %}</h2>
-
-  <p>
-    {% blocktrans trimmed %}
-      Network time server is a program that maintians the system time
-      in synchronization with servers on the Internet.
-    {% endblocktrans %}
-  </p>
+{% block configuration %}
 
   <h3>{% trans "Status" %}</h3>
 

plinth/modules/datetime/views.py

@@ -26,18 +26,11 @@ import logging
 
 from .forms import DateTimeForm
 from plinth import actions
-from plinth import package
 from plinth.modules import datetime
 
 logger = logging.getLogger(__name__)
 
 
-def on_install():
-    """Notify that the service is now enabled."""
-    datetime.service.notify_enabled(None, True)
-
-
-@package.required(['ntp'], on_install=on_install)
 def index(request):
     """Serve configuration page."""
     status = get_status()
@@ -55,7 +48,8 @@ def index(request):
         form = DateTimeForm(initial=status, prefix='datetime')
 
     return TemplateResponse(request, 'datetime.html',
-                            {'title': _('Date & Time'),
+                            {'title': datetime.title,
+                             'description': datetime.description,
                              'status': status,
                              'form': form})