kuksa-vss-init: rework into agl-vss-helper

Rework/replace the kuksa_vss_init script with a new agl-vss-helper
script that uses a configuration file for the list of VSS signals
and the values they should be set to.  It also will run in daemon
mode if the configuration includes a list of signals to perform
mocking as an actuator, and push any target values back out as the
current value.  This avoids needing to perform hacks around
directly feeding sensor values from applications for things where
we do not have an existing actuator backend (e.g. HMI units values).

Bug-AGL: SPEC-5042

Change-Id: I6d1e9d5fb72f7f23a3bb45fcda0a48e1a10c3863
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl-demo/+/29583
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account
Tested-by: Jenkins Job builder account