Support for k-means using RcppArmadillo with ClusterR package

[m-muecke]

• https://mlampros.github.io/ClusterR/reference/KMeans_rcpp.html
• https://github.com/tidymodels/tidyclust/blob/e6bd3420371677b41157ebb0883c30ab18d0a7b3/R/k_means.R#L172