revamp UI + show oncall/group

Summary:
Redesigns the bug reporting dialog:
- show information from `package.json`'s `bugs` field, where we can link to support groups or name oncalls.
- adds show/hide animation
- uses new button style

Reviewed By: jknoxville

Differential Revision: D13417287

fbshipit-source-id: 2948794e9b1f42bbd895981d5e4b0578a9b8ee2e

src/chrome/TitleBar.js

@@ -44,6 +44,7 @@ const AppTitleBar = styled(FlexRow)(({focused}) => ({
   paddingRight: 10,
   justifyContent: 'space-between',
   WebkitAppRegion: 'drag',
+  zIndex: 3,
 }));
 
 type Props = {|