smoothOnSurfaceRim should be true by default in GMG cycle

[bsumirak]

I think it is a relic from the early days of UG4 development that this is set to false by default.
Why would anyone not want to apply the smoothers to the surface rim as well? In general, this achieves better convergence rates. I think many users do not even know the option to enable this exists. And they should not need to bother.