[weston-ini-conf] Fix dependency issue with grpc in meta-agl-core

[weston-ini-conf] Fix dependency issue with grpc in meta-agl-core

grpc is not in the core layer but in meta-oe . Guard the dependency and only enable when
prerequisites are met. This also affects weston-ini-conf. We move this into meta-agl-demo.

Bug-AGL: SPEC-4707
Change-Id: Ia07cc8e32ac0c38586765985f367dae0cf8c429c
Signed-off-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/28510
Reviewed-by: Marius Vlad <marius.vlad@collabora.com>
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account