Dialog Forms: Fix layouts.
* ContainerGenerator.cs, ControlGeneratorLayout.cs, PetraFormDialog.yaml: Fix Button layout in the Button Panel at the bottom of the Form: make all Buttons the maximum Width of the widest Button) and space them correctly, and lay them out from right-to-left in the right Panel.

* The rest of the files in this commit are Dialog Forms whose layout has been improved. Mostly that meant aligning controls so that their 'borders' line up with the 'borders' of the 'Help' and either the 'OK' or 'Cancel' buttons, creating a consistent appearance. Also in several Forms the layout has been altered to create a better and more consistent Dialog GUI.