feat: add a to_json() output method

[lostmygithubaccount]

Is your feature request related to a problem?

in writing documentation/demos, I would like a to_json() method on tables for consistency with the other read_* and to_* methods

I'm not sure how JSON vs JSONL should be handled

Describe the solution you'd like

[ins] In [1]: import ibis
ibi
[nav] In [2]: t = ibis.examples.penguins.fetch()
i
[ins] In [3]: t.to_json("penguins.json")

What version of ibis are you running?

main

What backend(s) are you using, if any?

DuckDB mainly, but this should apply to any backend that supports JSON output

Code of Conduct

• I agree to follow this project's Code of Conduct

[NickCrews]

This is a dupe of #10413. Well, that one was opened after this, but that one has more action on it at this point, so I'm closing this in favor of that.