Add proper package.json files and release on npm

[Thalhammer]

Hi,
I really like the idea of porting litegraph to TypeScript. However the current form of this project makes it really hard to use the port.
This is somewhat similar to #1.
It would be really useful if you could add proper package.json files and release a version of it on npm, so that using it is as simple as npm install litegraph.ts.