Satisfy environment checks

* change PHP configuration to satisfy install tools checks for upload file size and xdebug.nesting_level
Correct file + folder permission configuration
Upgrade to 6.2

* install system extensions documentation, feedit, info, opendocs + recycler
* set compat_version
* document executed update wizard steps
Update database dumps

* apply update wizard changes to "clean" dump
* apply update wizard changes to demo content dump