Drop unused jquery multiselect widget

[elchukc]

• Partially resolves: Move away from jquery-ui #12980
• Somewhat simplifies Unify select mechanisms/widgets #1831

Summary

Removes 4 out of 5 uses of jquery-ui highlighted in #12980. The last one was a tooltip that was deleted in PR#37244.

I did my best to remove all jquery-ui uses in user_ldap/ but jquery is unfamiliar to me and it's hard to tell if I'm missing anything.

After a bunch of digging around in the documentation, I still cannot get any of the automated tests or php linting to work, although did run npm run lint:fix

TODO

• move global jquery-ui into file handling modules

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

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