Setup ELK integration. Kubernetes <-> Corfu

[Viacheslav]

Integrate ELK and Corfu cluster:

• An agent (dockerized filebeat agent) on corfu side (in corfu cluster) consumes corfu logs and send them to the ELK instance.
• The agent must be customizable via config files in corfudb-tests repository k8s directory.

Workflow:

• Jenkins runs an integration test
• After test finishes the work, run a filebeat agent on all the VM-s and collect all corfu logs
• The agent saves corfu logs in an elasticsearch index.
  TBD: There are 2 ways to go: save all IT test logs in one index or save each log in a separate index.
  Index template name could be ${jenkins_job_id}-${test_name}