create initial pull request

[davidchambers]

I recently found myself debugging sanctuary-type-classes/List@1 while getting to the bottom of stack overflows in a test suite. It turns out that implementing methods recursively is elegant but doesn't work for large structures. 😂

I spent time rewriting the functions with loops, and I now want to put that code somewhere so it can be used by the test suites of multiple projects. This repository is the logical place.

If people end up using this module and we encounter performance problems, we can investigate building atop funkia/list as originally planned.

/cc @paldepind