Re #8476 - Implemented `list_certificates` with unit tests.
Re #8476 - Finalized `create_certificate`. Update of swagger main.py
Re #8476 - Database FileAnchor utilization.
Re #8476 - Controller create certificate bugfix.
Re #8476 - Clarity update.
Re #8476 - Added as a part of the swagger-generated server stub. Imported required objects, SQLite3 thread issue hack (performance impact negligible, violates encapsulation), implemented `create_certificate`.