Add Python tests for Automat-CAM-KP

[gaurav]

This PR adds a test suite in Python for CAM-KP-API to cam-pipeline. Some of this code has been moved over from https://github.com/ExposuresProvider/cam-kp-api and the rest has been newly written for this.

There are three tests here:

• test_api.py: test the Automat-CAM-KP API endpoints.
• test_examples.py: tests the example files in examples/.
• test_curies.py: test a set of CURIEs to see if Automat-CAM-KP has information or not about them. This currently includes failing tests from https://github.com/ExposuresProvider/cam-pipeline/issues/101

I tried to move over the integration tests from CAM-KP-API, but I couldn't work out the easiest way to figure out how to move them over as a Scala project. I think these Python tests are easier to read and maintain, but I'm happy to be proved wrong.

Closes #94

Missing tests that will need to be handled separately (#123):

• POST /cam-kp/overlay is missing entirely -- I need an example of an overlay command to write an example.
• POST /cam-kp/cypher is a very basic test right now that extracts nodes and references, but not edges.

[gaurav]

Some of the tests need to be updated for the new release of Automat-CAM-KP that happened in December. I'll update these tests and resubmit them for review ASAP.

[gaurav]

Tests updated, ready for review again! There are some failing tests in tests/test_curie.py, but they've all been documented in https://github.com/ExposuresProvider/cam-pipeline/issues/101#issuecomment-1793934634 and will be dealt with there.