Make images sticky by default

[NikitaSalikov]

Changes Made:

• added a class to fieldset to default to sticky

• switched hidden button from anchorFloatDiv to floatImgDiv

Pull Request Checklist:

Pre-Approval

• There is a description section in the pull request that details what the proposed changes do. It can be very brief if need be, but it ought to exist.
• [N/A] Hotfixes should be branched off of the master branch and squash and merged back into the master branch.
• Features and backlog bugs should be merged into the Development branch, NOT master
• [N/A] All new text is preferably internationalized (i.e., no end-user-visible text is hard-coded on the PHP pages), and the spreadsheet tracking internationalizations has been updated either with a new row or with checkmarks to existing rows.
• [N/A] There are no linter errors
• New features have responsive design (i.e., look aesthetically pleasing both full screen and with small or mobile screens)
• Symbiota coding standards have been followed
• [N/A] If any files have been reformatted (e.g., by an autoformatter), the reformat is its own, separate commit in the PR
• Comment which GitHub issue(s), if any does this PR address:
  https://github.com/orgs/BioKIC/projects/6/views/14?pane=issue&itemId=29044724
• [N/A] If this PR makes any changes that would require additional configuration of any Symbiota portals outside of the files tracked in this repository, make sure that those changes are detailed in this document.

Post-Approval

• It is the code author's responsibility to merge their own pull request after it has been approved
• If this PR represents a merge into the Development branch, remember to use the squash & merge option
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• If this PR represents a hotfix into the master branch, a subsequent PR from master into Development should be made merge option (i.e., no squash).
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• Don't forget to delete your feature branch upon merge. Ignore this step as required.

Thanks for contributing and keeping it clean!

[Atticus29]

For me, the image doesn't seem to be sticky until I click the anchor button:

I think that the ticket wants it to start out as sticky (with the user being able to opt of out of this behavior).

Is it different on your side, @NikitaSalikov ?

[Atticus29]

Ok! Now it sticks by default, but is mis-aligned. Can we justify it right, somehow?

[MarkFisher-USDA]

Left a few more comments.

[MarkFisher-USDA]

Is there a way to do this without jQuery?
Also, the left attribute stil doesn't seem to be quite enough on my screen.

[Atticus29]

I'm really happy with the sticky behavior, and I'm ok with the draggable behavior.
However, when I make my screen really small, the image disappears from the viewport, and I can't scroll to access it. Is there any way to fix that behavior?