Migrate File Service to Anthos (GONRG-3407)

Description:

Create a new module called 'file-reference'. Use 'mongoDB' instead of 'Datastore'. Use 'minIO' instead of Google Storage'. Use 'rabbitMQ' instead of 'Pub/Sub'.

Changes include:

• New feature (a non-breaking change that adds functionality).

Changes in:

• Reference

Dev Checklist:

• Added Unit Tests, wherever applicable.
• Updated the Readme, if applicable.
• Existing Tests pass
• Verified functionality locally
• Self Reviewed my code for formatting and complex business logic.