Wire up API Explorer styling changes, refs T373

Summary:
  - Indicate the request method and endpoint being executed
  - Show whether a user is authenticated or not.
  - Added a textarea for inputting the request body

**TODO:**
- Make Add sample data button work
- Add the rest of the API endpoints
- Replace the textarea with this http://andrewcantino.com/examples/jsoneditor/example.html instead. I have to play around with it a bit

Test Plan:
  -#apiexplorer
  -Click on the endpoints
  -See the query execute

Reviewers: shadowhand, rjmackay

Reviewed By: shadowhand

Subscribers: sebm90, lkamau, srutto

Maniphest Tasks: T373

Differential Revision: https://phabricator.ushahidi.com/D200