Create npm module for converter

[katilius]

Currently, in order to use this module you need to:

1. Check out this repo locally
2. install jscodeshift globally or use npx to call jscodeshift globally.

This lib could be published as npm module in a way, that it is callable same as jscodeshift. So anyone who would want to use this, could execute some command like:

npx ast-i18n --config config.js --path my-project/src

[sibelius]

check this to run jscodeshift transformer as a cli

https://github.com/reakit/reakit/blob/master/packages/reakit-codemods/bin/reakit-codemods.js