Flesh out the use of the spacesuit

[Mikolaj]

Add air tank and require it to craft the spacesuit. Add skills Underwater Breathing and Void Breathing and let spacesuit boost both enough to pass deep water. Mark any not searched disengaged airlocks with pink, as with signboards currently. Let void-breathing actors search disengaged airlocks and find valuable things, e.g, docking guide poles. Perhaps make a few kinds of such airlocks, for variety. Optionally, don't reveal the airlock has no shuttle attached until searched. Loot is needed to make it fun even on the outermost level where no shuttle remains.

Related: add deep water and give water animals Underwater Breathing. Decide what happens with other actors in deep water and how AI makes relevant decisions. See LambdaHack/LambdaHack#148, LambdaHack/LambdaHack#147, LambdaHack/LambdaHack#145

A further plan would be to enable space walking and/or walking on the hull (one extra level, walking in reverse position using the suction in boots). That may also be how actors can get to other sections of the spaceship, once we include the other sections.

[Mikolaj]

The spacewalking part is related to LambdaHack/LambdaHack#88. In particular, it will be fun to add the outside of the ship, as walkable with spacesuit boots, with airlocks positioned in a mirror image and, ideally, with another section of the ship reachable from there.

Edit: funnily enough, when deck segments are connected by airlocks, an airlock on the top left of the level will match an airlock on the top right of the connected level. So there is a symmetry here, just as there is a symmetry when walking on the other side of the floor outside the ship's hull. It may be easier to start with this one, but keeping in mind the other one. Most of the code should be shared.