Integration with DIR Messages Resource

Identify the configuration that defines the Messages for the Jobs that should trigger SNMP INFORMs to be sent.
Modify the Messages Resuource so that the bsnmp script call is added as a new Mail message destination. In a fairly default installation, this could be
```
Messages {
  Name = "Standard"
  MailCommand = "/opt/bacula/bin/bsmtp -h <hidden> -f \"(Bacula) <%r>\" -s \"Bacula: %t %e of %n %l\" %r"
  OperatorCommand = "/opt/bacula/bin/bsmtp -h <hidden> -f \"(Bacula) <%r>\" -s \"Bacula: Intervention needed for %j\" %r"
  Mail  = "admin" = All,!Debug,!Saved,!Skipped
  MailCommand = "/opt/bacula/scripts/bsnmp -c /opt/bacula/etc/bsnmp.conf"
  Mail = snmp-dummy = All,!Debug,!Saved,!Skipped
  Append  = "/opt/bacula/log/bacula.log" = All,!Debug,!Saved,!Skipped
  Console  = All,!Debug,!Saved,!Skipped
  Operator  = "admin" = Mount
  Catalog  = All,Events,!Debug,!Saved
}
```
The key points to observe are
- The original Mail sending can be left as is, but all the entries for the new delivery method must follow the existing ones. So, MailCommand and Mail lines are added after the existing mail related entries.
- The actual address used with the bsnmp script is ignored, but needs to be provided per syntax definition. Put whatever you like.
- The actual message types used are not critical, but make sure that final Job reports get delivered. File lists, debug output, events and any other message types are, currently, ignored.
Verify configuration syntax as usual (bacula-dir -t)
Reload configuration. In bconsole, reload command.

Run a Job. After finishing, an SNMP INFORM should be delivered. When testing with snmptrapd (see above), information like

Jul 17 23:06:58 bsys-docdev snmptrapd[23559]: 2022-07-17 23:06:58 gnom.os.its-lehmann.de [UDP: [192.168.0.55]:45198->[192.168.0.44]:162]:
DISMAN-EXPRESSION-MIB::sysUpTimeInstance = Timeticks: (0) 0:00:00.00        SNMPv2-MIB::snmpTrapOID.0 = OID: ITS-Bacula-MIB::baculaNotifyJob        ITS-Bacula-MIB::baculaJobName = STRING: moria-home        ITS-Bacula-MIB::baculaJobResult = INTEGER: ok(0)

should be logged.