autobuild: introduce build scripts

- Add agl autobuild script to silence build
  warnings on yocto.
- Add linux autobuild script to build with
  the sdk
- Migrate to afb helper library version to
  successfully build with the sdk using
  autobuild script.

NB: The 2 autobuild scripts are based on the
latest version of the autobuild script, but they've
been customized to (i) work with the existing qmake
files and (ii) the 'update' and 'package-test'
targets have been removed.

Bug-AGL: SPEC-2164

Change-Id: I7196665b65693bfe5557a0008fb36aa7b38068a5
Signed-off-by: Raquel Medina <raquel.medina@konsulko.com>