QtComp: Implement set_maximized and set_fullscreen to have something

We only support single screen for now in the api, so pretty basic still

Change-Id: I629df2378e7d3b16024090dcf620a239be4b4496
Reviewed-by: Jan Arne Petersen <jan.petersen@kdab.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>
Remove unwanted api

Change-Id: I2e2d57df508b08594ec937e19259d156e5b3b547
Reviewed-by: Jan Arne Petersen <jan.petersen@kdab.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>