cleanup: Remove expired Bacula 9 ports:

2024-09-30 sysutils/bacula9-client: Unsupported. Please migrate to bacula15-server
2024-09-30 sysutils/bacula9-client-static: Unsupported. Please migrate to bacula15-server
2024-09-30 sysutils/bacula9-docs: Unsupported. Please migrate to bacula15-server
2024-09-30 sysutils/bacula9-server: Unsupported. Please migrate to bacula15-server
2024-09-30 net-mgmt/nagios-check_bacula9: Unsupported. Please migrate to bacula15-server