STORM-567: Move Storm Documentation/Website from SVN to git

This is a work in progress on migrating the storm website/documentation to git in order to make it easier for the community to contribute updates. If there is enough interest in contributing, we can create a feature branch to better enable collaboration.

This is more or less a straight copy of the current website content, with the following enhancements:

* Use bootstrap for layout to make docs mobile/tablet friendly
* Restore syntax highlighting for code snippets
* add a documentation index page listing all doc links.

I haven't worked on branding (e.g. integrating the official logo, color themes, etc.).

I'd love collaborate if anyone is interested, especially anyone with better front-end skills than I. ;)