move to readthedocs

@jrha I updated the script so it recreates exactly what is in https://github.com/quattor/configuration-modules-core/tree/docs
So:
 - removed headers user for jekyll
 - adapted data structure (docs/components/<mdfile>)
 - write mkdocs.yml

should save you some sed time. :)


Does errno 17 correspond to "this already exists"? I think it might be easier for others to follow if this was written:
```
if not os.path.exists(compath):
    os.makedirs(comppath)
```