Rename package to 'flipper'

Summary:
- rename package `'sonar'` > `'flipper'`
- rename package `'sonar-static'` > `'flipper-static'`
- rename package export from `window.Sonar` to `window.Flipper`

Reviewed By: passy

Differential Revision: D9851181

fbshipit-source-id: 34d4447c3b287496b3d20ddb54471ce777ec74e1

src/ui/components/ToggleSwitch.js

@@ -48,7 +48,7 @@ type Props = {
  * **Usage**
  *
  * ```jsx
- * import {ToggleButton} from 'sonar';
+ * import {ToggleButton} from 'flipper';
  * <ToggleButton onClick={handler} toggled={boolean}/>
  * ```
  */