Add a new method to set time

Before this change there are a various components that set the system
clock by directly calling AlarmManager.setTime(). This change exposes a
new method on TimeDetector to use when setting the device time manually
(e.g. via settings) and modifies some callers to use it.

The intent is to later restrict the number of distinct processes that
can manipulate the device system clock directly so that all time changes
go through the time detector service, which can enforce policy, log
the reasons for changes, and so on.

Bug: 140712361
Test: atest com.android.server.timedetector
Change-Id: I9300dba868ed61249d0848b0dd4b953996161bda