Update datatables

[yubiuser]

What does this PR aim to accomplish?:

I thought I just give it a shot.

Package	From	To
datatables.net	2.3.8	3.0.1
datatables.net-bs5	2.3.8	3.0.1
datatables.net-buttons	3.2.6	4.0.1
datatables.net-buttons-bs5	3.2.6	4.0.1
datatables.net-select	3.1.3	4.0.0
datatables.net-select-bs5	3.1.3	4.0.0

Certainly will break things at the beginning.

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[yubiuser]

Ok, it now renders without errors. I think it doesn't look bad (at least not worse than development looks right now). Ready for input.

[DL6ER]

The CSRF change needs a word in the PR body: presumably DataTables 3 no longer picks up our global $.ajaxSetup() now that jQuery is optional for it. Without that, the next person rediscovers it.

Two things follow. It is ten copies of the same line - one definition in utils.js would do, and it avoids a const csrfToken collision should two of these scripts ever share a page.

And it was only added to the ajax blocks, which are all GETs. If $.ajaxSetup() is dead here, our POST/PUT/DELETE calls are the ones to worry about. Worth confirming before this lands.