Separate versioning.rst into abi versioning and abi policy guidance, in
preparation for adding more detail to the abi policy. Add an entry to the
maintainer file for the abi policy.
Signed-off-by: Ray Kinsella <mdr@ashroe.eu>
Acked-by: John McNamara <john.mcnamara@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>