Migrate demo issuer services to Sovrin StagingNet

[esune]

To promote interoperability, we want to migrate our demo issuing services to the Sovrin StagingNet.

The services that will be migrated are:

• [ ] email-verification-service
• [ ] conf-book
• [ ] unverified person issuer
• [ ] healthbc issuer (PROD)
• [ ] esr1 issuer (PROD)
• [ ] esr2 issuer (PROD)
• [ ] medlab issuer (PROD)
• [ ] safe entry verifier service (PROD)
• [ ] safe entry c19 verifier service (PROD)
• [ ] a new instance of vc-authn connected to Sovrin StagingNet should be deployed as well.

Tasks:

• [ ] register DIDs of existing agents on StagingNet
• [ ] switch agents to using StagingNet
• [ ] deploy vc-authn instance pointing to StagingNet (use devex-con-prod namespace)
• [ ] update vc-authn configurations with the appropriate clients for the PROD apps
• [ ] add proof-request configurations for PROD apps to vc-authn
• [ ] update config.json for the PROD apps to use the new vc-authn endpoint for authentication

[WadeBarnes]

@esune, I think this is now a duplicate of https://github.com/bcgov/von/issues/341.

[esune]

@WadeBarnes you are right. #341 is better structured and more detailed, I will close this issue and use the other one to track the work.