blueprint-vending-machine-ui-application: Add systemd service

To start app in graphics session after control app.

Control app is started before UI app to avoid inconsistencies

vending-machine-ui-application: Move service in package directory
vending-machine-ui-application: Fix systemd integration

Relate-to: https://git.ostc-eu.org/OSTC/planning/core-os/-/issues/233
Forwarded: https://git.ostc-eu.org/distro/oniro/-/merge_requests/357


Thanks-to: Andrei Gherzan <andrei.gherzan@huawei.com>
Signed-off-by: Philippe Coval <philippe.coval@huawei.com>