[ENH][bp/r47153] Allow providers of virtual servers with preconfigured databases to pass these database credentials to the Tiki installer. More in http://doc.tiki.org/System+Configuration

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@47154 b456876b-0849-0410-b77d-98878d47e9d5