net: provide IP-related API on any OS

net: provide IP-related API on any OS

Users of <rte_ip.h> relied on it to provide IP-related defines,
like IPPROTO_* constants, but still had to include POSIX headers
for inet_pton() and other standard IP-related facilities.

Extend <rte_ip.h> so that it is a single header to gain access
to IP-related facilities on any OS. Use it to replace POSIX includes
in components enabled on Windows. Move missing constants from Windows
networking shim to OS shim header and include it where needed.

Remove Windows networking shim that is no longer needed.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Ranjit Menon <ranjit.menon@intel.com>