Clean up and enable DSE feature

[ducky64]

Enable the DSE feature globally. Clean it up so the entry points are non-obtrusive, they're behind a DSE submenu in the context menus

Also cleaning up of the DSE feature interface:

• Axis ticks use SI prefix instead of the 1e9 mess
• Adding a first objective / search space no longer brings up a (nonfatal) IDE error - using .lastOption instead of .last
• Gate unproven objective behind the feature enable config
• Add DSE objective insert on port parameters - it should be possible to do the example purely graphically