eal: split compat header file

eal: split compat header file

The compat.h header file provided macros for two purposes:
1. it provided the macros for marking functions as rte_experimental
2. it provided the macros for doing function versioning

Although these were in the same file, #1 is something that is for use by
public header files, which #2 is for internal use only. Therefore, we can
split these into two headers, keeping #1 in rte_compat.h and #2 in a new
file rte_function_versioning.h. For "make" builds, since internal objects
pick up the headers from the "include/" folder, we need to add the new
header to the installation list, but for "meson" builds it does not need to
be installed as it's not for public use.

The rework also serves to allow the use of the function versioning macros
to files that actually need them, so the use of experimental functions does
not need including of the versioning code.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Andrzej Ostruszka <amo@semihalf.com>