ZEPPELIN-64 - Migration of zeppelin-project.org to jekyll

This is initial template, see [Readme](README.md) on how to try it locally.

- [x] create initial jekyll project structure 
- [x] create layout using bootstrap 
- [x] migrate existing content from previous site

On content migration:
- [x] change hightligh syntax to gihub-flavored markdown
- [x] in community.md keep only one mailing 
- [ ] ~~migrate documentation to Sphinx~~ moved to #11