Make dynamic modeler module more user friendly

[lassoan]

We originally intended to make provide this module as backend infrastructure (not directly for users). But it is getting pretty useful directly, so we may consider implementing this improvements:

• Hide input model by default to make results easier to see. At least on the first update. Maybe add a display section (or widgets next to the node selectors) to change model visibility, opacity, and color. Maybe we could add a new node selector widget, which has about the same API as qMRMLNodeComboBox, but it would be based on subject hierarchy combobox and could also display an eye icon, and a color selector.
• Disable Apply button until all required inputs are set (or at least display an error message in a status area when the Apply button is pressed and model cannot be generated)
• Add a button to create new plane or curve
• Currently boundary cut only works if curve is in "shortest distance on surface" mode. Either remove this limitation (e.g., automatically snap each curve point to the closest surface point) or when "boundary cut" rule is selected, set the input curve mode to "shortest distance on surface" mode and the surface node to the input surface.
• Change subject hierarchy icon of rules that have auto-update enabled (if it's easy to do)
• ... more ideas will be added here

[arpinerap]

We talk in Slicer Forum to add Substract Tool if could be possible in future.

[lassoan]

We talk in Slicer Forum to add Substract Tool if could be possible in future.

I've added a new issue to track this request (#38). Please next time create a new issue instead of commenting on a different issue (improving the usability of existing features is not the same as adding new features). Also, please click the ❤️ icon at this post because we will not implement Boolean operations before remote module support is added to VTK.