RFC: Edit distances for strings

## Checklist

> Please ensure the following tasks are completed before filing an issue.

- [x] Read and understood the [Code of Conduct][code-of-conduct].
- [x] Searched for existing issues and pull requests.
- [x] If this is a general question, searched the [FAQ][faq] for an existing answer.
- [x] If this is a feature request, the issue name begins with `RFC:`.

## Description

> Description of the issue (or feature request).

This RFC proposes the inclusion of edit distance functions to compare two strings, for example the [Levenstein distance](https://en.wikipedia.org/wiki/Levenshtein_distance).

## Related Issues

> Does this issue (or feature request) have any related issues?

No.

## Questions

> Any questions for reviewers?

What would be a good place inside of `stdlib` for string distance functions?

[code-of-conduct]: https://github.com/stdlib-js/stdlib/blob/develop/CODE_OF_CONDUCT.md

[faq]: https://github.com/stdlib-js/stdlib/blob/develop/FAQ.md