chore: Add integration test for Python stack

[lym953]

What does this PR do?

Add a Python stack to integration tests, so that the test will compare the snapshots generated after vs before, to check if a PR causes unexpected changes on the stack to be deployed.

The stack was copied from examples/python-stack. I had to copy it because I was unable to find a way to just reference the existing stack.

Motivation

Adding more tests to make it safer to deploy changes.

Testing Guidelines

Additional Notes

Types of Changes

• [ ] Bug fix
• [ ] New feature
• [ ] Breaking change
• [x] Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• [x] This PR's description is comprehensive
• [ ] This PR contains breaking changes that are documented in the description
• [ ] This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• [ ] This PR impacts documentation, and it has been updated (or a ticket has been logged)
• [ ] This PR's changes are covered by the automated tests
• [ ] This PR collects user input/sensitive content into Datadog