Migrate to m-site-p with Markdown sources only

[kwin]

Currently the site is based on Jekyll which requires ruby. This is a hassle to setup for the different platforms (particularly on Mac OS) and although it is stated in the readme.md:

You can also use the script provided to run the Java implementation of Jekyll if you don't want to install Ruby/Jekyll on your system.

the referenced jekyll.sh is neither part of this repo nor properly linked.

Also the current HTML sources are hard to maintain, therefore leaving emitting html to some tool and focus only on the content seems a logical step to me and although it is stated in the readme

The M2Eclipse website is a Jekyll-based website that is primarily written in the Markdown format, with a bit of plain HTML.

there are no markdown sources at all in this repo currently.