Feat/slack notification handler

[Andreass2]

Description

• Added a scheduled query which runs each 5th minute for logs of 500 errrors in broker.
• if logs are found and email is sent and forwarded to slack.

Related Issue(s)

• Sett opp Slack-varsel til vaktordningen for ukjente feil #378

Verification

• Your code builds clean without any errors or warnings
• Manual testing done (required)
• Relevant automated test added (if you find this hard, leave it and we'll help out)
• All tests run green

Documentation

• User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[Andreass2]

When this is merged into main, we will start sending errors to slack. If you want to see a test email notification as a step of the review let me know.

As of now it logs all 500 errors with 5 minute intervals. (max 1 email per 5 min).

[Ceredron]

Does it log to our normal Slack channel or a separate one?

[Andreass2]

Does it log to our normal Slack channel or a separate one?

No. As requested by Eirik Mikkelsen it logs to a general one for all product teams.