healthd: a.h.health@2.0-service.override removes healthd

Removes healthd from the build if -service.override
is provided. This encourages developers to deprecate healthd
for their devices when they can.

When -service.override is used, framework manifest needs
to remove the /backup instance as well; this can be done
by including manifest_healthd_exclude.xml in
DEVICE_FRAMEWORK_MANIFEST_FILE.

Test: build and boot on 2016/2017 Pixel devices
Test: build and boot on a new device
Test: lshal and vts_treble_vintf_test on all these
      devices
Bug: 77541952

Change-Id: I25744feaad3034441cd7a96a5343d4ce3eedc288