Module structure and github package

[PPP01]

Hi, I had some trouble to integrate this module by github directly.
The main problem was that SimpleAutocomplete.svelte was not compiled and no index.js/mjs were generated.

According to this article, I made some modifications to package.json:
https://blog.jim-nielsen.com/2018/installing-and-building-an-npm-package-from-github/

1. I added "prepare": "npm run build" to scripts
2. I moved the index.js/mjs to a /dist folder. That's more common structure IMHO.

After these changes, the module from github worked like a normal npm-package. If you like, I make a pull-request.