Upgrade jQuery, jQuery UI, SlickGrid, and QUnit to latest stable versions

[actapia]

I'm not sure if there's any interest in making these upgrades in this repository, but I have a branch in my fork of EMPeror at https://github.com/actapia/emperor/tree/jquery_3 where I've updated some of the JavaScript dependencies. I've also replaced PhantomJS in the GitHub workflow with node-qunit-puppeteer, since the former is no longer supported.

Should I make a pull request?

[ElDeveloper]

@actapia yes, that would be great!! My main request would be to break this down into smaller PRs. For example, one upgrading the CI system, one upgrading jQuery, etc.