Combine Installer and Maintenance Tool

The installer and maintenance tool is not intuitive to new Qt users. 

We should have just an installer (name to be decided), which is used both in the first installation and later to maintain the existing installations. 

When the installer is launched, it should search for (or read somewhere) the existing installations. User would pick up an installation, which is then managed by the installer with the updated UI). If no folders are found, the installer would do similar installation to today without writing the maintenance tool to the installation folder. 

This should be split into two stories: one for combining the update/install views, the other one for having a single installer installation.