[tweak] Docking services toggles are confusing if ship doesn't have any DockClasses

[oznogon]

If nothing can dock with a ship, the GM Tweak menu shouldn't show them toggles for services provided to docked ships, because they're useless.

[hemmond]

Not sure, but I believe there were talks with ECS branch, that docking classes could be modified mid-scenario.

[daid]

The ECS branch handles this quite different, where an entity has a DockingBay component if things can dock to it. Instead of the current code where just everything has these properties but it's not clear when they are valid or not.