agl-ic-container: Fix host configuration when using agl-demo

agl-ic-container: Fix host configuration when using agl-demo

Changes:
- Switch to pulling in a agl-ic-container.inc include file from the
  feature local.conf.inc template to simplify development.
- Add include files for the host ("default" in BitBake) multiconfig
  to allow disabling agl-demo and related features in the host build.
  This reduces the impact on the host image when using the images
  from meta-agl-demo as guest containers.  At present the
  "agl-selinux" feature is left alone, as support pretty much needs
  to be present in the host to allow using it at all.  This likely
  needs to be investigated further and discussed with respect to the
  IC EG requirements.

Bug-AGL: SPEC-4703

Change-Id: I833fa8754f0044552a8b775bcc06c4ccd3fcac3e
Signed-off-by: Scott Murray <scott.murray@konsulko.com>