Add incident label to enable measurement of time-to-restore

[Ceredron]

Description

Shared with other repos in Altinn:
https://github.com/Altinn/labels/labels?q=incident
Used centrally to measure time-to-restore

Related Issue(s)

• #{issue number}

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)