CICD testing integration

[harshi-puli]

Added python based testing units to test various aspects of the data generation pipeline.

The following changes were made:

• ci.yml (outlines github actions)
• test/test_generate.py (tests the actual generated output: valid yolo labelling, null cases)
• test/test_overlay_single.y (tests if overlay abides by certain rules and if the functions are actually returning images/labels.) + Also creates the target images for the test_smoke.py.
• test/smoke.py (tests the data generation pipeliine against a small dataset within test/fixtures)
• test/fixtures/{backgrounds or targets} - the basic flat color images that are used to test the data generation pipeline in practice.

Process Testing:

• GitHub actions worked within ci-cd-testing branch.

[kvaikunthan]

Why are there edits to generate.py? Need to check if those are safe.

[kvaikunthan]

Ok so I think you may have not pulled from main before making the changes 😭

[kvaikunthan]

lgtm