Add optional basic auth: fix bug 1021307

Add support for jinja2 deploy templates
Port nginx.conf template to jinja2 with conditional basic auth
Add auth.conf template
Fix bug 1021315: Ensure static files are world-readable and executable.
Add conditional cron jobs for db and media backup

Add hourly db backup cron job if settings.PG_BACKUP_DIR
Add nightly rm backups 4 days old if settings.PG_BACKUP_DIR
Add hourly media rsync if settings.MEDIA_BACKUP_DIR