jQuery Deprecations

[rfultz]

Summary

What we're after:
While doing the Webpack 5 upgrade and JavaScript overhaul, I ran into and made notes of several jQuery deprecations. If we still must use jQuery, at least this PR will prune where we've been using outdated parts.

Related issues

Completion criteria

• nothing touched by these changes is broken
• other deprecations have been removed, too
• Move from jQuery.click #6750
• Move from jQuery.change #6751
• Move from jQuery .focus, .blur #6753
• Move from jQuery .bind, :first, .hover, .keyCode, :last, .submit, .trim #6752