Refactor how Desktop install and locate configuration files.
Fix the Neo4j Desktop vmoptions include path, and add an option to the uninstaller, to also remove configuration and log files.
Revert the change that removed the Neo4j Desktop Install4j license injection point.

Also add a user-local plugins directory to the classpath.
Add a plugins directory feature.

 - Add a plugins directory to the installation directory where users (or administrators) can add jar files with plugins and extensions.
 - Added a button to the settings panel that opens Explorer (or the platform directory browser) in the plugins directory.
 - Obviously also added it to the launcher classpath. This was the hard part, because we wanted to put the directory under $APPDATA, but this could not be made to work with the current version of Install4j.
Fix the window-close-database-shutdown behaviour that I broke in my eager refactoring.
Get the name of the sub-directory under APPDATA from the installer, instead of hard-coding it.
Merge pull request #1546 from chrisvest/refactor-desktop-config

Enable server extensions in Neo4j Desktop