Hard deprecate connect_to_etn() and reexport

[PietrH]

Previously on this dev branch, connect_to_etn() was no longer exported, and used internally as a helper. In this PR, a new helper is created to take over this work, and connect_to_etn() is re-exported, but hard deprecated: it always returns a lifecycle warning message, and it only returns NULL. All SQL helpers were adapted to use this new helper. Tests were changed over so both connect_to_etn() and the new helper are covered.

We decided to do it this way so older scripts that have con <- connect_to_etn() at the top are met with a deprecation message rather than a missing function.

connect_to_etn() is no longer neccesairy. Functions that need credentials will prompt the user for them.

I also added to NEWS and made a small change to a vignette.

[PietrH]

Ready for review

[peterdesmet]

One comment. Would extend test with function call with parameters.

[PietrH]

Made requested changes, ready for a second look if you have time. I'd appreciate your opinion on the changes to the vignette.

If not, let me know and we can merge.

[peterdesmet]

I updated the vignette (please verify it's correct) and simplified the test to just make use of lifecycle::expect_deprecated()

[PietrH]

I'm not a 100% sure how often you'll be prompted for them, but at least every time you click "Quit Session" so I think that's close enough.

Thanks for the review Peter!

[PietrH]

The 2 tests in connect_to_etn() still fail:

Failure (test-connect_to_etn.R:5): connect_to_etn() returns deprecation warning when used
`connect_to_etn(username = "my name", password = "my password")` did not throw the expected warning.

Failure (test-connect_to_etn.R:8): connect_to_etn() returns deprecation warning when used
`connect_to_etn("my name", "my password")` did not throw the expected warning.

I'm looking into it, but would be grateful for any ideas!

[PietrH]

I documented the behaviour of the tests and added skips for them, I'm now merging so this doesn't block the beta release.

I'm also planning on creating a minimal test package to see if I can replicate this behaviour, and if so, I'll go looking for help on https://forum.posit.co/

[PietrH]

Thank you both for the constructive comments and contributions!