Apk isn't generated during the build step but in deployement one

IMO it will be better if the apk would be build during the build step, cause if the deployment failed the apk isn't up to date as expected (build succeeded). An other issue is that the clean on the project don't remove the previous apk, it can be confusing.

This little improvement will help us a lot to do our releases management.

The name of the apk need also use the project name instead of "QtApp-debug.apk"