Split SupplicantStateTracker and refactor

- Move SupplicantStateTracker into a seperate file. In the
process clean up code that needs to be present only in SupplicantStateTracker

- Retry twice for password failures

- Clean up supplicant state handling. Dont treat supplicant states
as HSM what values. Instead, just retain SUPPLICANT_STATE_CHANGE

- Add event logging in SupplicantStateTracker

- Move scan handling out SupplicantStateTracker

Change-Id: I083e1c40ef5a858164493b1440b82c5751b3bfb5