Moving notifications and keyguard status higher in split shade lockscreen

Decreasing Y position of keyguard status view and decreasing padding of notifications.
Padding of notifications is calculated instead of provided with resources because notifications already have margin that is flexible and would be likely overriden in overlays.

Fixes: 204568802
Test: KeyguardClockPositionAlgorithmTest
Change-Id: I3f9c60ec03bfdc3efc347d3dd1cb1b66c6dcd865