Replaced issuer.js's OpenBadges.ROOT w/ OpenBadges.getRoot().

This will be needed for other scripts/modules/etc. to be able to
get at the root URL.
Added a very simple OpenBadges.connect() implementation in the built issuer.js.

The implementation just redirects the user's browser the backpack's access
page (the controller+route for which haven't been implemented yet).

Ultimately an intermediary will be doing the work of figuring out what
the backpack's endpoints are.