Add possibilities for easier project setup (generating the .user file)

After cloning a project from the VCS repo, several steps are needed to set it up for working on it and compiling.

It is currently possible to create .pro.shared files that cover some of the aspects, but especially everything need for compilation and running cannot be set there.

Items that could be covered by such a setup wizard are:

• Query specific (QMake-CONFIG) variables from the user to enable/disable features or subprojects
• Specify a minimal Qt version that is needed
• Create build configurations for different platforms (desktop, mobile, embedded) if the Kits are available
• Set up environment variables for build and run configurations
• Create run configurations with command parameters
• Set up a specific run configuration as default

The list may be extended by lots other useful things