Set up health checks confirming Kakfa connectivity as producer

[acn-sbuad]

Description

We need a health check to confirm the connectivity between the e-mail service and the Kafka broker.

Considerations

• [x] Separate topic for the health check or simply a different consumer-group?

Development tasks

• [x] Add liveness and readiness probes in the helm chart
• [x] Implement health check in notifications
• [x] Implement health check in notifications email
• [x] QA
• [x] Manual test is complete (if relevant)

Test

• Introduce an error or fault in some way and verify that health check fails and alarms are activated
• [x] Ensure alert rule picks up on errors

Acceptance criteria

• [ ] Health check is enabled for the e-mail microservice
• [x] Health check is enabled for the notification microservice

[acn-sbuad]

Confirming connectivity with producer health check for now. Cannot guarantee that the consumer will read from the partition that a new health check message is written to without creating a flaky check. Implemented and tested ok for notifications

[acn-sbuad]

Using AspNetCore.HealthChecks.NpgSql attempts to read from the yniqul table which the user has no rights to do (?). Anyways it ends with an exception `

Unhandled exception. Npgsql.NpgsqlException (0x80004005): Exception while reading from stream

Custom health check towards postgre has run successfully