Changing user inactivity and warning dialog timeouts

Increasing the inactivity timeout to 90 seconds to accomodate the longest
app. demo video for retail. Also, removing the warning dialog by setting
the countdown timeout to 0, so it can be re-enabled by overriding the value
through gservices if needed.

Bug: 30426773
Bug: 30866394
Change-Id: I6735943adfaf3d210ed9eb9163b5c7ce8dcf53ec