[NEW] www/py-django18: Add Django 1.8.4 to the tree

Create a new www/django18 port using www/py-django17 as a base.

• Use CHEESESHOP (Geo-based CDN) as the default MASTER_SITES
• Update COMMENT to more closely match upstream
• Add version and LTS suffix to COMMENT
• Update CONFLICTS and de-scope to CONFLICTS_INSTALL
• Fix whitespace alignment and improve readability

Django 1.8 Release Notes:

https://docs.djangoproject.com/en/1.8/releases/1.8/