API: libpacemaker: Move crm_rule functionality to libpacemaker

pcmk__check_rules() makes its own copies of the passed-in data, so it's
effectively const, even though it can't be completely due to non-const
function calls.

The test output no longer includes "crm_rule:" prefixes since we use
out->err() instead of g_set_err().

Closes T58

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>