CLOUD-789 - add test to check password leaks in the logs

[ptankov]

Create a test to start the cluster with some fixed passwords and then let the script loop over pods/containers and check the logs for the strings.

[it-percona-cla]

All committers have signed the CLA.

[tplavcic]

I think we need to add it to:

• haproxy test: after: "desc 'checking all haproxy pods point to the same writer'"
• pitr test:
  • after step: "run_backup "$cluster" "on-pitr-minio""
  • after step: "desc "done gtid type""

[JNKPercona]

Test name	Status
affinity-8-0	passed
auto-tuning-8-0	passed
cross-site-8-0	failure
demand-backup-cloud-8-0	passed
demand-backup-encrypted-with-tls-8-0	passed
demand-backup-8-0	passed
haproxy-5-7	passed
haproxy-8-0	passed
init-deploy-5-7	passed
init-deploy-8-0	passed
limits-8-0	passed
monitoring-2-0-8-0	passed
one-pod-5-7	passed
one-pod-8-0	passed
pitr-8-0	passed
pitr-gap-errors-8-0	passed
proxy-protocol-8-0	passed
proxysql-sidecar-res-limits-8-0	passed
recreate-8-0	passed
restore-to-encrypted-cluster-8-0	passed
scaling-proxysql-8-0	passed
scaling-8-0	passed
scheduled-backup-5-7	passed
scheduled-backup-8-0	passed
security-context-8-0	passed
smart-update1-8-0	passed
smart-update2-8-0	passed
storage-8-0	passed
tls-issue-cert-manager-ref-8-0	passed
tls-issue-cert-manager-8-0	passed
tls-issue-self-8-0	passed
upgrade-consistency-8-0	passed
upgrade-haproxy-8-0	passed
upgrade-proxysql-8-0	passed
users-5-7	passed
users-8-0	passed
validation-hook-8-0	passed
We run 37 out of 37

commit: 31ea845
image: perconalab/percona-xtradb-cluster-operator:PR-1472-31ea8453