Multimedia Map (and bundled Multimedia Upgrades)

- redesigned multimedia map is cleaned up and now supports the same controller that bulk upload uses
- lots of cleanup of old unused files
- fixes a bug from not having overwrite existing media checked

From a previously postponed commit (https://github.com/dimagi/core-hq/pull/909):

- YUI Upgrade to 3.9 to support HTML5 upload as an alternative to flash when flash isn't present. If neither are supported, a message is displayed encouraging the user to switch to a different browser.