Update jquery to v4.0.0

[yubiuser]

What does this PR aim to accomplish?:

Feeling brave today. After AdminLTE4 and Datatables don't depend on jquery anymore, I thought I give it a try. Also, bootstrap-select is gone (see here), which was a blocker before.

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[yubiuser]

This time, it will break with the completely outdated https://github.com/mouse0270/bootstrap-notify because this function was removed https://api.jquery.com/jQuery.isFunction/#jQuery-isFunction-value

Maybe we could use Bootstrapv5's toast as a replacement:
https://getbootstrap.com/docs/5.0/components/toasts/

[yubiuser]

I let the AI replace the bootstrap-notify with bootstrap-toast and it worked quite well. Needs some tweaking of the design, but works as intended.

ADD

Continues here: #3843 as it is independent of jquery.

[rdwebdesign]

@yubiuser,

I was thinking and I don't see a good reason to migrate to jQuery 4:

• All current plugins work with jQuery 3.

• Bootstrap 5 and AdmiLTE v4 doesn't need jQuery at all:
  we can use any jQuery version, or not use it.

• Datatables 3.0.1 doesn't require jQuery:
  In this case, I think we should use jQuery to keep the current code, just to avoid rewriting all datatables code. We can use jQuery 3.

• jQuery 4 removes support for some older browsers.
  I'm not sure how many users are still using older browsers, but there are probably a few ones that will complain.

My suggestion is:

Let's finish the plugins migration (including datatables, notify and maybe others), but without jQuery 4.

Then, we focus on things we need to finish release the new web interface, like adjusting all themes.

What do you think?