Add support out of three image install to support agl demo ivi guests

Add support out of three image install to support agl demo ivi guests

Existing AGL IC container integration build host and all guest
using multi config.  When we want to add support agl demo ivi
guests, multiconfig based integration require to long build time
by single build tree.

This patch enable support out of tree image install to support.
This method support prebuild ext4 image installation.  This method
realize to reduce build time for AGL IC developer.

Bug-AGL: SPEC-4766

Change-Id: Id4ba092ce89c05bad3440e75845e6602bb0a50ab
Signed-off-by: Naoto Yamaguchi <naoto.yamaguchi@aisin.co.jp>