[Development] [Request] Add Info to QDebug

[Kurt Pattyn]

Qt currently supports the following ‘severity’ levels for logging: Debug, Warning, Critical, Fatal and System.

I propose to add the following levels: Info and Error, with associated methods qInfo() and qError().
Particularly, the Info severity can be interesting to have applications output log messages that are not warnings, but also not debug messages. Error would fit between Warning and Critical.