Tests to strengthen ingestion logic

[lewismc]

@renato2099 this is an opportunity for us to both list any additional test cases we think can build confidence in the ingestion logic. Please ad them to the list below...

Unit Tests

• tests covering different container files as per patool
• test that parallel ingestion of files from different datasets results in the creation of two datasets and tags
• test that parallel ingestion of files from the same dataset results in the creation of one dataset and tag with different submission's

Functional & Integration Testing

• Use testcontainers-python which facilitates the use of Docker containers for functional and integration testing. Specifically we should use the PostgresContainer class to validate all of our PostGIS interactions.