Remove all date 'now' methods from Painless

[jdconrad]

As the title says.

This closes (#20762).

[nik9000]

We should add some documentation about how to actually get now in a followup I think.

[rjernst]

Lgtm. I don't think we need to document how to get now, as this is something people shouldn't be using in scripts. That is the entire reason for #20762.

[jdconrad]

I think @nik9000 might have meant document how to get the equivalent of now by passing it in as a param? @rjernst Thanks for the review.

[nik9000]

I think @nik9000 might have meant document how to get the equivalent of now by passing it in as a param?

Indeed.

[s1monw]

w00t thanks for the quick reaction on this @jdconrad