240 quantile pivot

[dajmcdon]

Closes #240

@dsweber2 This isn't a "layer" but you should be able to call it directly on the predictions and get out something much closer to the submission format.

• There was already the _wider() version. But naming is better.
• The _longer() version should be what you want.

This function is a necessary precursor to #237

[dsweber2]

awesome, thanks for this! If it isn't too gnarly, is it possible to change the column names from q and tau to something user defined/default to quantile/value? If not, it's easy enough to pass this through rename after

[dajmcdon]

On the q/tau issue, this isn't the only place in the package we have this problem. See also #147 (now 1 year old). We need to standardize these throughout. I'll put it on the Tooling agenda.

Now it's own issue #242.

[dajmcdon]

This is a breaking change. Needs a version bump and/or a shim for the dperecated pivot_quantiles().

[nmdefries]

thought: These names were updated in #243 but since the functions got moved around here vs that branch, merging them will probably get hairy. The #243 changes might not percolate to this new file, so reminder to check.

[dajmcdon]

Definitely hairy, unfortunately.