Fix Bug 920268 - Change /firefox/ redirect

Point *only* to /firefox/new/, removing all version logic, while
preserving querystrings, if present.

Add name and query parameters to bedrock.redirects.util.redirect
and change default behavior to pass query params to redirect
location.

Replace url('firefox') with url('firefox.new') in templates

Remove unused bedrock/redirects/tests/urls.py
Merge pull request #1284 from jgmize/bug-920268

Fix Bug 920268 - Change /firefox/ redirect