netlink: add a basic rtnetlink parser of rule messages

netlink: add a basic rtnetlink parser of rule messages

* defs.h (routing_table_ids): New xlat prototype.
* rtnl_rule.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* defs.h (ip_type_of_services, routing_table_ids): New xlat prototypes.
* netlink_route.h (decode_fib_rule_hdr): New prototype.
* configure.ac (AC_CHECK_HEADERS): Add linux/fib_rules.h.
* netlink_route.c (route_decoders): Add RTM_DELRULE, RTM_GETRULE,
and RTM_NEWRULE.
* xlat/fib_rule_actions.in: New file.
* xlat/fib_rule_flags.in: Likewise.

Co-authored-by: Fabien Siron <fabien.siron@epita.fr>