3rd part of the layer/profile rework [2/2]

This is the last part of the layer rework series.

Notable changes are:
- move demo specific recipes to the demo (dlt, web-runtime mocca-usb)
- wayland-ivi-extension moved to the meta-agl-demo layer for now.
- web-runtime moved here (from appfw layer to allow console-only builds with appfw)
- adapted packagegroups and agl-features

v2: squashed with commit on sandbox to form single commit (tnx, Scott)
v3: inclusion of old packagegroup-agl-image-ivi (TODO: refactor and include in profile packagegroups. Tnx, Stephane)
v4: base packagegroup-agl-demo-platform on packagegroup-agl-profile-graphical-qt5
v5: fix MOST_DRIVERS_append (disable due to FTBS)
v6: re-add RDEPENDS for virtual/pulseaudio-config

Bug-AGL: SPEC-145
Bug-AGL: SPEC-1422

Change-Id: I20bd5b9a957ea54a7ecd08bd4f8b99a32266c9c8
Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>