Add image scale bars display option

[d33bs]

Description

This PR adds a display option for scale bars within the images displayed.

Closes #115

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.

[d33bs]

@jenna-tomkinson - in addition to other areas for this change, I'll need your help to make sure the scale bars are accurate within the notebook, thanks in advance!

[jenna-tomkinson]

LGTM! I added some questions for you to address prior to merging. Also I recommend updating the example/add some documentation on how we found the um_per_pixel info. I found it via the metadata of the image.

[d33bs]

Thanks @jenna-tomkinson ! Merging this in.