Revert^2 "[Pod] Move SystemClock to util.time pod."

This reverts commit ae49d748.

This moves the interface and the implementation and also moves the
Dagger that binds the two together.

Bug: 307607958
Flag: EXEMPT refactor
Test: m SystemUI
Test: m SystemUIComposeGalleryLib

Reason for revert: CL topic has build fix

Change-Id: I0b0fe5697342bfb69659789f3f31ca2343d9ac2d