Update translation setup

Follow new infra setup for translations, see spec
http://specs.openstack.org/openstack-infra/infra-specs/specs/translation_setup.html
for full details.

Prepare babel-django.cfg qnd remove babel.cfg.
This repository is django related. So, follow Django repos convention in OpenStack.

This basically renames
designate-dashboard/locale/designate-dashboard.pot to
designatedashboard/locale/django.pot to follow Django POT file convention.

setup.cfg babel entries are kept as this repository has
only python files and it still works, they have been updated for new
setup.

Change-Id: I388c6b92b9e9d7a0c9d7b81b4c495a65088e4856

setup.cfg

@@ -31,15 +31,15 @@ all_files = 1
 upload-dir = doc/build/html
 
 [compile_catalog]
-directory = designate-dashboard/locale
-domain = designate-dashboard
+directory = designatedashboard/locale
+domain = django
 
 [update_catalog]
-domain = designate-dashboard
-output_dir = designate-dashboard/locale
-input_file = designate-dashboard/locale/designate-dashboard.pot
+domain = django
+output_dir = designatedashboard/locale
+input_file = designatedashboard/locale/django.pot
 
 [extract_messages]
 keywords = _ gettext ngettext l_ lazy_gettext
-mapping_file = babel.cfg
-output_file = designate-dashboard/locale/designate-dashboard.pot
+mapping_file = babel-django.cfg
+output_file = designatedashboard/locale/django.pot