Add system user as separate entry in jaas-secret.
Make metrics exporter not print SASL_USER_PASSWORD to log on startup.
Make provisioning wait-for-available-kafka optional,
since init containers aren't wrapped by service mesh and break with such.
Add SASL support to kafka-provisioning.
Add pre and post provisioning scripts, to increase flexibility.
Add extraProvisioningCommands, which are run after topic provisioning in the
same parallel execution loop.
Signed-off-by: David Olofsson <account@sidju.se>