Migrate integration tests to testcontainers

[ndepaola]

Description

• Had a few mins spare tonight, so I thought I'd clean up our test configuration a bit to spin up postgres and elasticsearch with testcontainers
• Build time is about the same but github actions is less hacky + running the tests doesn't overwrite data in your local elasticsearch instance anymore

Checklist

• [x] I have installed pre-commit and installed the hooks with pre-commit install before creating any commits.
• [x] I have updated any related tests for code I modified or added new tests where appropriate.
• [x] I have manually tested my changes as follows:
  • No manual testing required
• [x] I have updated any relevant documentation or created new documentation where appropriate.
  • None required