Add docsify static website generator

[Omurbek]

Docsify has good website UI. https://docsify.js.org/#/

[Fred de Villamil]

Hello,

This looks interesting, but doesn't bring much compared to the Jeckhill I've put in place https://fdv.github.io/running-elasticsearch-fun-profit/ specially the sidebar won't generate the table of contents recursively. Best regards