Add installed 3rd party software with Nuxeo Windows installer to system path

With the current Windows installer, it seems as though all 3rd party software is present, but not properly installed.

Steps to reproduce:

• Uninstall any versions of LibreOffice and PostgreSQL on machine.
• Download and run nuxeo-10.10-SNAPSHOT-20190117-setup.exe.
• Select the options to install both LibreOffice and PostgreSQL.
• Follow instructions in installation wizard until installation is complete.
  => C:\Nuxeo\3rdparty contains ffmpeg, gs, ImageMagick, java, misc and pdftohtml
  => PostgreSQL 11 is installed.
  => LibreOffice 5.2.3.3 is installed.
• Run Start Nuxeo.bat by double-clicking its icon.
• Open a browser and navigate to http://localhost:8080/nuxeo
• Follow the wizard.
• Wait until the server restarts (+10 minutes! )
  => Warnings in server.log about several programs and converters not being found in system path.
  => Office documents not rendering in Web UI.