Facebook requires a callback when using the `.ui()` method now. I don't
know when this changed, but the share button is currently broken on
course certificates.
Facebook documentation of the `.ui()` method:
https://developers.facebook.com/docs/javascript/reference/FB.ui/
* updated the flags for social media sharing
* added facebook feed ui to share public url
* update the condition logic
* update the code as per suggestion and added pick new style for share buttons
* update the css class reference
* update the bok-choy test
* updated description and some text touch-ups
* moved the JS related to facebook into separate location
* js formatting
* Add trailing comma per chrisndodge
* Add wait to fix flaky test...maybe
