recipes: extending steps

[frankiethull]

thinking about steps that could be added to this package.

starting with these:

• step_kpca_*
• step_kha_*

potentially others:

• step_kcca_*
• step_kfa_*

all four should be easy wins, the functions are within {kernlab} and {recipes} has a step_kpca_rbf() and step_kpca_poly() to start off.

additional info here: https://www.tidymodels.org/learn/develop/recipes/

[frankiethull]

another one, related to #6 (comment)

https://rdrr.io/cran/mildsvm/src/R/kfm_nystrom.R

[frankiethull]

recipe branch is called polenta 🌽
https://github.com/frankiethull/maize/tree/polenta

• - step_kpca_laplace
• - step_kha_laplace
• - step_kpca_tanh
• - step_kha_tanh