Improve readme for a general audience
Improve readme for a general audience

ADD an explanation of the expected file structure in the content/, which
will not be pushed to the git repo.

agdsn/sipa,MarauderXtreme/sipa,lukasjuhrich/sipa,agdsn/sipa,lukasjuhrich/sipa,fgrsnau/sipa,lukasjuhrich/sipa,fgrsnau/sipa,lukasjuhrich/sipa,MarauderXtreme/sipa,agdsn/sipa,agdsn/sipa,fgrsnau/sipa,MarauderXtreme/sipa