[1/2] Add triggers to change profile based on AP

Add data structure mWifiTriggers to store triggers per profile.
Add network change listener to switch to profile

Change-Id: I97e360d7783d3b0e2bbd70fe7a9a866d8c0fa7cd
Avoid unnecessary FindClass("java/lang/String").

Use previously retrieved global reference instead.
Check for NULL after creating the global reference.

Change-Id: I21670d2ef0f63ddb5801dd21e7e56359e5519479