New rs.js module docs

[raucao]

I found out that jsdoc-to-markdown allows using templates, so that’s what I did in the shares module now. Works like a charm:

• https://github.com/skddc/remotestorage-module-shares/blob/master/README.md
• https://github.com/skddc/remotestorage-module-shares/blob/master/main.hbs
• https://github.com/skddc/remotestorage-module-shares/blob/master/package.json#L10