Add plugin to help find unuse files, remove some files

[brmscheiner]

Pull request checklist:

• Features and bugfixes should be PRed into the develop branch, not main
• All text is internationalized
• There are no linter errors
• New features support all states (loading, error, etc)

Thanks for keeping it clean! Feel free to merge your own pull request after it has been approved - just use the "squash & merge" option.

[Emily-Ke]

unused-webpack-plugin hasn't been updated in two and a half years. It also only has 9 reported issues though. Would you rather use something that is more actively maintained?

Some of the images that were removed are used as mock data in the components that you didn't remove. Was that intentional?

[Atticus29]

LGTM

[brmscheiner]

@Emily-Ke i did play around with a couple other libraries, unused-files-webpack-plugin and webpack-unused. but in the end this was the one that i got working really easily and it seems to be working fine. maybe i should take a quick look at the open issues and see if anything looks damaging

i am okay with losing the mock data, just wanted to keep the UI elements that we might use later. probably could clean up more soon

[brmscheiner]

ok, i looked at the issues and didn't find anything serious. mostly just feature requests and a couple people who couldn't get it working for them.