Update KafkaProducer to return false instead of throwing an exception. Create alert rules to detect cases

[SandGrainOne]

Description

Currently Producer exceptions are thrown to the service calling the producer.
As the service cannot do anything with e.g. a non existing topic, so it should rather return false and log the exception.

We should have alert rules to monitor exceptions of this type in Azure.

Tasks

• Update producer logic in notifications and notifications email
• Add alert rule to terraform rule set
• QA
• QA alert rules: https://dev.azure.com/brreg/altinn-studio-ops/_git/altinn-studio-ops/pullrequest/731
• Test

Test

• adjust topic name in env variables, restart pods and run use case tests

Acceptance criteria

• In case of exceptions an alert should be sent to slack

[acn-sbuad]

Manual set up alert verified in at22. will be rolled out with next aks update