During User onboarding to BYO, migrate Authentications to the new secrets manager (and vice versa)

When a user wants to bring their own secrets manager, they will go through the flow to add the credentials.

The backend will accept these credentials and after that migrate all of the user's current authentications to the new instance of secrets manager, this way all of the user's secrets are in their specified account. 

The opposite will happen if/when the user removes their credentials.