Enable running audio services on host for KVM demo

Changes:
- Add agl-kvm-host-audio feature for configuring other changes.
- Make installation of packagegroup-agl-ivi-service-platform in the
  KVM host versus IVI images dependent on the agl-kvm-host-audio
  feature.  Some recipe dependencies are tweaked by the feature
  being specified to avoid accidentally pulling things into the
  IVI guest images.
- Add KVM demo specific configuration for applications affected by
  running the databroker on the host versus in the IVI guest, and
  use it if the agl-kvm-host-kuksa feature is enabled.

Bug-AGL: SPEC-5082

Change-Id: I3a6e6216a90e4d260c20f0b048e6332466aef4ff
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl-demo/+/29702
ci-image-boot-test: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jenkins Job builder account