Url patterns (re)defined only in urls.py

[darbula]

Urls for contacts, news and vacancies were defined in multiple places:

• urls.py,
• models.py - in url_path and
• menus.py - in url_attribute.

This situation prevents changing/translating the default urls (i.e. contacts/ news/ etc). In this commit url patterns in urls.py are given names and then reverse is used to resolve urls where needed i.e. in Entity.get_related_info_page_url or in URLModelMixin.get_absolute_url.

Url patterns are named so that their name can be deduced from url_path and url_attribute when needed.

[darbula]

This pull is closed in favor of pull #71.