Move query scheduling time to MdnsQueryScheduler

Instead of having query scheduling time split between MdnsQueryScheduler
and QueryTaskConfig, where QueryTaskConfig has the base run time and
MdnsQueryScheduler does backoff, consolidate it all in
MdnsQueryScheduler.

This allows QueryTaskConfig to only contain parameters used when the
task runs, and not scheduling info.

Test: atest
Change-Id: Ie060802ff2d13c1cea339955d8b609ba95f762f2
3 files changed