ISIS-1335: remove simpleapp-archetype.adoc, changed the few references to instead reference the relevant 'getting started' chapter of ugfun (user guide fundamentals). Also removed ug.adoc, was just there for old links. Previously removed rg.adoc.
ISIS-1333: removing references to jetty-console in the docs. Also improvements to website home page layout (screenshots), and fixing ref to archetype page, and improving the archetype page. Also ... ... also moved sections in the developers guide for lombok and agileJ into appendices of that guide.