A folder's files are linked before its subfolders, and the rigid body
files are linked as one flat sequence. ListShape is the one file that
does not fit this order.

| Old | New |
|---|---|
| RigidBody/Shape/<Kind>/phys<Kind>Shape.cpp | RigidBody/Shape/phys<Kind>Shape.cpp |
| RigidBody/Shape/<Kind>/phys<Kind>RigidBody.cpp | RigidBody/physRigidBody<Kind>.cpp |
| RigidBody/Shape/List/physListShapeRigidBody.cpp | RigidBody/physRigidBodyListShape.cpp |
| physHavokMemoryAllocator.cpp | System/physHavokMemoryAllocator.cpp |
| StaticCompound/physStaticCompound{,Mgr,RigidBodyGroup,Util}.cpp | System/ |
| StaticCompound/physStaticCompound{Info,Autogen}.cpp | System/physStaticCompoundInfo.cpp |

The original has the type infos' cleanup functions just before
StaticCompoundInfo's functions, so the merged file defines the
reflection data first, with plain static cleanup functions as in
Havok's generated reflection code. Template instantiations would be
emitted after the rest of the file.

(AI assisted using Claude Fable 5.1 and Claude Opus 5.5)

The same BoxShapeParam class is used for two different shape classes
(BoxShape and BoxWaterShape) so it's more natural to move the factory
function to the shape class itself

What we currently call BoxBody, CapsuleBody, etc. is actually
BoxShape, CapsuleShape, etc. (those classes encapsulate Havok shapes)

So this commit renames Body -> Shape and Shape -> ShapeParam.