Show community account last login and count info on admin page

The collection facility was added in
[200~9e70a4e0c32f8db0178f05dac4c1fca7b317e7c5, but no way was added to
view it. To make it a  bit more useful, add a static set of info on the
user edit page in /admin/ that shows the last login and number of logins
per site.

pgweb/util/widgets.py

@@ -0,0 +1,12 @@
+from django.forms.widgets import Widget
+
+
+class TemplateRenderWidget(Widget):
+    def __init__(self, *args, **kwargs):
+        self.template_name = kwargs.pop('template')
+        self.templatecontext = kwargs.pop('context')
+
+        super().__init__(*args, **kwargs)
+
+    def get_context(self, name, value, attrs):
+        return self.templatecontext