Automotive: Initial sources to support another variant

This is an automotive-only change (see the target branch).

This MR includes the default CONFIGs for automotive and some macros into the SPEC file to support the automotive variant.

v1: Right now, the CONFIGs look good, but the SPEC file is still complaining about some sbupackages.
v2: Following the same SPEC logic of RT, automotive now is able to generate automotive-only packages based on the variant workflow (not as a flavor). v3: More refinement in CS9 automotive CONFIGs parity.

Signed-off-by: Julio Faracco jfaracco@redhat.com