Yarn/NPM package

Maybe it was already discussed, but I didn't find any related issues on this repository.

Having all the font on GitHub is great to get last update easily and use self-hosting.

But it would be more convenient for theme packages using one of these fonts if they are proposed on Yarn/NPM.

I see two possibilities:

- A simple `google-fonts` package with all the font inside.
- A package per font. For example `gfont-lato`. Better to download only what we need.

Both possibilities may be combined.

What do you think?