F3 lab is missing many old features

[Goober5000]

Many features have not yet been re-implemented after the lab was migrated to imgui. The current lab is pretty much just a ship and mission background viewer. The old lab allowed the tweaking of a whole bunch of settings, allowing many experiments to be performed without restarting the game engine. (This was well-suited to its designation as a "lab".)

Here are some screenshots from 19.0.0.

Ships:

Weapons: