Consider replacing Moment with something smaller / modular

Moment is a huge monolith, and [it's a big problem](https://github.com/moment/moment/issues/2373). In my case, it's the second largest dependency after React. Here are their unpacked numbers (after `gzip` they shrink proportionally):

```
react: 645.64 KB (17.20%)
moment: 454.54 KB (12.10%)
...
```

I'm as much of a Moment fan as the next guy, but this is way too many kilobytes. Something like [`date-fns`](https://github.com/date-fns/date-fns) could be a better fit. I wanted to switch, but I rely on this excellent component too much to give it up.

Please, let me know if you're open to this, and whether you intend on doing this yourself or not.