rigidbody: Add function to perform convex sweep test

This is a experimental collision detection function, so the API might
change in the future.

Note: The simulation needs to be stepped before this function can be
used, otherwise the rigid body world might not be valid.

Patch [#34989]  Bullet Convex sweep test API
by Vilem Novak (pildanovak), thanks!

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56195 954f8c5b-7b00-dc11-b283-0030488c597c