Restore Qt compositor cluster demo image

Restore Qt compositor cluster demo image

Changes:
- Added the required backend plugin options for running with Qt's
  compositor to the PACKAGECONFIG variable in the qtbase recipe
  bbappend.
- Restore an updated recipe for the agl-cluster-demo-qtcompositor
  image, with updates to the associated packagegroups for the app
  framework removal.
- As part of the above, the duplication of the profile-cluster-qt5
  package naming has been clarified in the qt5 versus qtcompositor
  packagegroups with new -wayland and -egl suffixes, with the previous
  plain -qt5 name aliasing the wayland option to maintain expected
  behavior.  This avoids packaging conflict errors if building both
  types of cluster demo image in the same tree.
- Restore updated cluster-gauges-qtcompositor recipe required for the
  image.
- A simple systemd unit file has been added for the cluster-gauges
  application and is currently installed as a system session unit.
  Some rework of the agl-session scheme is required to run as a
  user unit, the intent is to address that in one of the 13.0.x point
  releases.

Bug-AGL: SPEC-4283

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: Id79484c025fef067d7d47eaf783768e700a9dc8d