Fix Qt cluster demo images

Fix Qt cluster demo images

The rework of the demo images done for SPEC-5138 missed some things
for the Qt cluster demo images, so add the extra demo vs non-demo
configuration file for use in the "preconfigured" image, and update
the image recipes to get things work with respect to developer
expecations.

Additionally:
- The databroker access token for cluster-dashboard was out of date,
  a copy of the one for the Flutter cluster dashboard has been copied
  in to restore expected behavior.
- The Flutter cluster demo has also been tweaked slightly to match
  the style used in the other image recipes.

Bug-AGL: SPEC-5229

Change-Id: I8cc9cfb67c31ace95e6ac36e4259099223f7d802
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl-demo/+/30174
ci-image-build: Jenkins Job builder account
Tested-by: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account
Reviewed-by: Naoto YAMAGUCHI <naoto.yamaguchi@aisin.co.jp>