Add MAP end-to-end testing GitHub Action

[tomaroberts]

Either using the sample data in /tests/data or an entirely new test data subset, we need to implement an end-to-end GitHub Action in order to test the end-to-end process works.

e.g. GitHub Action should look in an input folder and produce an RT Struct file in an output folder.

Ideally this would be using the MAP container (see #24), but fallback would be to use monai-deploy exec app -i input/ -o -output/ instead (assumption being that performance is expected to be the same as containerised MAP).

[tomaroberts]

See here for WIP implementation: #26

As of today, GHA fails during MONAI Deploy MAP build process at Step 19. Have also tested with minimal simple-imaging-application from MONAI Deploy repo and that doesn't work either. Suggests MAP-related issue. Potentially memory issue with GitHub Action env given containers are >15GB.

Raised Bug ticket here too: Project-MONAI/monai-deploy-app-sdk#431