Convert hardcoded URLs to dynamic ones

[chosak]

This change removes usage of hardcoded URLs in favor of using Django's django.core.urlresolvers.reverse and {% url %} template tag to better support cases where this app is being deployed under a website's subdirectory.

For example, if this app is deployed under a /eregs-2.0 subdirectory, regulation URLs should be under /eregs-2.0/regulation/etc, and not under a hardcoded /regulation/etc.

In addition, a couple of hardcoded /static references in templates have been converted to use of Django's {% static %} tag, for a similar reason.

Changes

• Hardcoded URLs instead now use django.core.urlresolvers.reverse and {% url %}.
• Hardcoded references to /static now use {% static %}.

Testing

• All existing unit tests continue to pass, and working site functionality continues to do so.

Checklist

• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows the standards laid out in the front end playbook
• Passes all existing automated tests
• Visually tested in supported browsers and devices

[grapesmoker]

Looks great.