Styleguide: Further clarifications on URL pattern naming

This should cover all cases.
pootle_profile: Use reverse() instead of hardcoded urls
Get TITLE and DESCRIPTION from siteconfig directly

Instead of changing django.conf.settings at runtime which we should not
be doing:
    https://docs.djangoproject.com/en/dev/topics/settings/#altering-settings-at-runtime

Fixes bug 3150.