apmanager: Rename "chromeos" -> "brillo" in include paths and namespaces

libchromeos is transitioning to libbrillo and chromeos namespaces
and include directory is changing to brillo.

Bug: 24872993
TEST=built for aosp and brillo, all unit tests pass on dragonboard
Change-Id: I4c6efbc5bbf80d251e5d91bc3db49f02bc0e4732
26 files changed