Update Replication Creation Flow

Two things need to be updated with how the ingest server currently handles creation of replications.

1. For the initial replications, we should check for the existence of a fixity value for both the Tag Manifest and Token Store, and ensure that both StagingStorages are active. Once this is confirmed, we can create replications.

2. For any ad-hoc replications, we'll need to do the same as the above with the caveat that we might need to write out a new Token Store.