Implement collections/sortBy ( closes #1061 )

[LionC]

This PR adds a sortBy function to the collections module.

sortBy allows you to sort an array without mutating it by an arbitrary selected value like this:

const people = [
    { name: 'Anna', age: 34 },
    { name: 'Kim', age: 42 },
    { name: 'John', age: 23 },
]

const sortedByAge = sortBy(people, it => it.age)

sortBy was part of the original proposal (see #1065 and its links) and in the discussions following the merge of the initial set of functions, seemed to have consensus, which is why I went forward and implemented it.

Notes on the implementation: I chose to limit the selector function to common sortable types. I looked into different options and they all seemed hacky or inconvenient for users of the function. The approach in the PR seemed like the best compromise between not caring about return types at all (and thus not saving people from hard to track bugs) and specifying every possible case.

This closes #1061

[kt3k]

The test cases look good to me.

[kt3k]

@LionC LGTM. Nice work!