Add about box in firmware upgrader and network configurator

[stephanemagnenat]

Now that we have proper support for about box, it is easy. The following steps have to be done:

• add an about button and launch the about box
• link with qtabout
• initialize resource in main
• load translator
• add proper organization name for the sake of cleanness

[stephanemagnenat]

This is not very critical so I am moving this issue to 1.7.