Make a SecretService for backend

[UsamaEquinorAFK]

Describe the improvement you would like to see
Add a new service for retrieving secrets from keyvault to reduce redundant code.

How will this change existing functionality?
Will have one place where all secret fetching is handled, and less code in different services.

How will this improvement affect the current Threat Model?
N/A - Feel free to add anything here if I missed something.

[tsundvoll]

Great name for a service

[andchiind]

I feel that the threat model could be affected, if we're not careful

[UsamaEquinorAFK]

I agree, as it says it's a proposed improvement. If there is something specific which anyone thinks should be considered we can look over that but as I understand we can't fetch secrets if we haven't completed az login step so we should be safe.

[oysand]

Check if it is possible to do well through the appsettings

[aeshub]

This issue has automatically been marked as stale as there has been no activity for 60 days.

[Christdej]

Appsettings is good enough