CaseFile: Dynamically build the casefile identifier using uuid and db index increment

[cypher4859]

The CaseFile model currently uses the date and and a string to make the casefile identifier and this won't work for us long term. Instead we need a way to dynamically build the Casefile identifier with OBSID, the index in the database, and a UUID. The methods have already been stubbed out, they just need to be filled in with the implementation of how to do it. Below are some good resources for researching the topic:

Resources:

• Python Docs on UUIDs
• Retrieving Objects from Database