Adding testing framework documentation

[axiomcura]

modified from EmbeddedArtistry

Description

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Please succinctly summarize your proposed change.
What motivated you to make this change?

Please also link to any relevant issues that your code is associated with.

What is the nature of your change?

This PR adds CytoSnake testing framework documentation. A preview of this PR can be viewed here: https://cytosnake-testing-docs.readthedocs.io/en/latest/

Other changes:

• added logo to the website (top-left corner)

• Bug fix (fixes an issue).

• Enhancement (adds functionality).

• Breaking change (fix or feature that would cause existing functionality to not work as expected).

• This change requires a documentation update.

Checklist

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• I have read the CONTRIBUTING.md guidelines.
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• I have performed a self-review of my own code.
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• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• New and existing unit tests pass locally with my changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have deleted all non-relevant text in this pull request template.

[gwaybio]

This looks great @axiomcura !

I made several in-line suggestions, mostly aiming to improve clarity and consistency. I also had some comments on small improvements to the figures. Also, the figures are not rendering in the testing rtd (but maybe this is expected until after merge)

Is the strategy to add the remaining unittest and workflow test documentation as you actually add their implementation alongside?

No need for me to re-review prior to your merging, but please don't hesitate to ask any questions.

[d33bs]

Nice work! Overall I thought things looked good and left a few comments for your consideration. Please don't hesitate to let me know if you have any questions.

Note: I wasn't able to see the preview at https://cytosnake-testing-docs.readthedocs.io/en/latest/ (the link appears to result in a 404).

[d33bs]

This is beautifully written, great job!

[d33bs]

This comment is in regards to the filenames of this and the other similar README-*.md files within the docs/tests dir: do these files require README in the name? If they don't, consider defaulting to a filename without README-. In seeing the other files which reference these outside the docs/tests directory, consider moving the content there.

[d33bs]

Consider removing this image if it isn't required (it looks like the svg is referenced instead).

[axiomcura]

Applied all changes! Merging! Thank you all !