CTDB: support Samba 4.9+

With Samba 4.9+, all ctdbd parameters have moved to config files.
Generate a new /etc/ctdb/ctdb.conf file during ctdb startup, based on RA
configuration.

Event scripts in Samba 4.9+ are also no longer enabled/disabled based on
file mode. Use the "ctdb event script enable/disable" helpers, which now
work without a running ctdbd.

Fixes: https://github.com/ClusterLabs/resource-agents/issues/1196
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Noel Power <noel.power@suse.com>
Signed-off-by: Amitay Isaacs <amitay@samba.org>