Run andi integration and unit tests in parallel

[c-m-duncan]

Description

Trying to get unit and ingestion tests to run in parallel to speed up deployments that are delayed by flakey tests.

Upside: should increase build time by 2 minutes per run or so

Downside: this does cause the install to happen multiple times, so slightly more space is used. Storing the compiled application / docker container between jobs is technically possible, but rather difficult and not done by this pr.

Reminders:

• Be mindful of impacts of changing Major/Minor/Patch versions of each elixir app
  • If updating patch version, are you sure there are no chart changes required to maintain functionality? If so, you should bump minor version instead.
  • If updating Major or Minor versions , did you update the sauron chart configuration?
• If changing elixir code in an "app", did you update the relevant version
  in mix.exs?
• If altering an API endpoint, was the relevant postman collection updated?
  • If a new version of smart_city is being used (new fields on a struct), were the relevant postman collections updated?