build-appliance-image: Support for VirtualBox guest additions
Add support for VirtualBox guest additions.
The additions are built inside the Build Appliance VM.
For this to be possible, the environment for out-of-tree kernel module builds
must be present and set up properly.
A README file with detailed steps on how to build the guest additions is placed
in the home directory of the user "builder" as well.
The main purpose of the guest additions is to allow sharing folders between
the host and Build Appliance VM.
[YOCTO #8073]
Signed-off-by: Juro Bystricky <juro.bystricky@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
