Remove net oriented sample editor

This removes the UI and all code related to the net oriented sample designer.

added GUI cleanup labels

requested review from @j.wuttke

Could it be that this big reduction leaves some more functions, in other places, unused? Which tools would you apply to detect those?

approved this merge request

• I was checking/following the includes of each removed file
• I was using ReSharper to detect unused code

Right now, there is nothing unused left afaics. However, certain code was/is only present to support the deleted sample editor. E.g. many of the tooltips have a been set for the net oriented sample editor, and have been set a second time for the layer editor (because for the old editor the tooltips had to contain the unit, for the new one the units are not allowed due to the new switch-unit-feature). Such code has to be removed still. It is not "never used", but "not necessary". Therefore it is not detectable by any tool, only by experience.

In the next MRs I will address things like this (next to some UI improvements/changings to harmonize apperarance and code usage).

merged

mentioned in commit dd2010b7