Move testing only dependancies from `requirements.txt` to `dev-requirements.txt` for our containers that use python

[robertmitchellv]

Action Requested

In our test.yaml workflow there is an conditional statement that now allows for splitting up requirements into:

• a requirements.txt file that holds the requirements that the container needs to run and nothing more
• a dev-requirements.txt file that holds the requirements for testing (including pytest) and other needed dependencies for development work

The Message Parser is an example of how this can work, so we'll need to set up something similar for the remaining containers that use python and have a requirements.txt file. This will help us move towards smaller container images even if just by a small amount.

Acceptance Criteria

When we've ensured that:

• only dependencies our containers need to function are in their associated requirements.txt and nothing else;
• that the testing dependencies (even if just pytest) are in their associated dev-requirements.txt
• and that our testing (both unit and integration) workflows are passing.