Fixing the site - Removing broken msi from the Downloads, etc

It seems that Spark 2.5.8 msi installers are very infamous for their bugginess. Some bugs were reported by me long time ago, some were confirmed by Todd Getz. As they cause problems and then cause another and another threads in the forums, maybe we can remove them from the Downloads page? Maybe with the next release we could have a more reliable msi installer.

P.S. also maybe we should remove (hide) current roadmaps from the site, also obsolete screenshots in the Products pages.