mo:base/Array, mo:base/functional/Array, or both?

[rvanasa]

mo:base/Array mostly comprises of functional operations similar to the data structures in the mo:base/functional directory, but it also includes one imperative-style function, Array.sortInPlace().

Do we want to provide separate imperative / functional modules? This is a bit of a murky in-between case, so I'm curious to hear more opinions about how we could approach this.