Add red dot capability for visualizing the center of compartments

[d33bs]

Description

This PR adds functionality for CytoDataFrame to display a red dot where the center of a compartment is, relative to the image object crop. I also made some minor adjustments to existing tests to help enable us to check for red or green pixels in output. During testing @jenna-tomkinson noticed that the bounding boxes might not be operating correctly so we raised #92 to help address this in the future (nothing here should change bounding box capabilities).

Closes #77

What kind of change(s) are included?

• Documentation (changes docs or other related content)
• Bug fix (fixes an issue).
• Enhancement (adds functionality).
• Breaking change (these changes would cause existing functionality to not work as expected).

Checklist

Please ensure that all boxes are checked before indicating that this pull request is ready for review.

• I have read and followed the CONTRIBUTING.md guidelines.
• I have searched for existing content to ensure this is not a duplicate.
• I have performed a self-review of these additions (including spelling, grammar, and related).
• These changes pass all pre-commit checks.
• I have added comments to my code to help provide understanding
• I have added a test which covers the code changes found within this PR
• I have deleted all non-relevant text in this pull request template.

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[jenna-tomkinson]

LGTM! 🎉

[d33bs]

Thanks @jenna-tomkinson ! After making some changes based on your comments I'll now merge this in.