Media cleanup

The goal of this branch is to clean up old static asset dependencies pointing to the media server in order to clean up old unnecessary files currently hosted on media.

Changes:

* Bring favicon, app icon, social media icons, and webtrends tracking script into SCPRv4
* Delete old Social Media flatpage (also deleted in Outpost flatpages) with approval from Patrick and Kristen
* Add webtrends.v2.js to asset precompile
* Clean up unneeded external image references on Podcasts index view and My Ballot partial.