[RDF] Improve user guide with cheat sheet
[RDF] Improve user guide with cheat sheet

and update the documentation to the new behaviours, e.g. lazyness of cache, possible lazyness of Snapshot, Report is now an action.

root-mirror/root,root-mirror/root,karies/root,root-mirror/root,karies/root,karies/root,karies/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,olifre/root,olifre/root,olifre/root,olifre/root,karies/root,karies/root,root-mirror/root,olifre/root