Add options to set the location of the separate collision mesh or move to correct location

[adnanmunawar]

When using the separate "collision mesh" option, AMBF will place the collision mesh origin at the origin of the Rigid Body (or Ghost Object). This can confuse when using the Blender ambf_addon, as the separate collision mesh can be moved around in Blender and thus the user may expect the collision in AMBF to follow suit, which it will not.

[adnanmunawar]

AMBF will set the origin of the collision mesh to be where the origin of the rigid body is. Therefore if one wants to offset the collision mesh, this has to be accomplished by offsetting the origin of the collision mesh. This commit implements two options which are discussed below.

1. Move collision mesh to body origin:
   Clicking this button will move the collision mesh such that its origin coincides with the origin of the rigid body. This does not change the collision location but only shows what AMBF already implements and is meant to avoid confusion.

2. Use current location of collision mesh:
   Clicking this button will keep the collision mesh wherever it is in the Blender scene, and change its origin to be where the rigid body is (internally this offsets the origin of the mesh by moving the vertices). This option may come in handy if one wants to move the collision mesh and have this reflected in AMBF.