[misc] add sample app for gamepad

Impacted Suites: webapi-sanityapp-w3c-tests
Impacted TCs num: New 1, Update 0, Delete 0
Unit test Platform: Android
Android test result summary: Pass 0, Fail 1, Blocked 0

Comments:
1. The sample app  base on Firefox browser.
2. The spec is not supported in android.


Singed-off-by: Xu, JianfengX <jianfengx.xu@intel.com>