Move static assets into vegancity app

This is done so that all apps can collectstatic at the root level static/ folder.
Collect static apps to one place

Fixes #321 on github

Issue #321 was caused by grappelli expected static apps to be collected
to the static/ root. Now, app static files are collected.
Merge pull request #327 from steventlamb/topic/fix_static_assets

Topic/fix static assets