T2D-66 Accession files by UUID
Created by: pabarcgar
- Added a generic UUID generator, that will generate name based UUIDs
- Added JPA entity and repository for managing files
- AccessionGenerator transformed from interface to abstract class to add some generic code that will be common to all the implementations
- Added File Accessioning Service and repository implementations
- Added a File accessioning REST server with a POST endpoint to generate accessions