deprecate convert_to_wide

[kellijohnson-NOAA]

@k-doering-NOAA do you think that we can remove https://github.com/ss3sim/ss3sim/blob/eeb0b33a7d30eca93c586a1724fa774e3f21fc44/R/get-results.r#L613

Seems like the long results have been around long enough that we might not need to provide support for the "old" way.