Loads a TUM trajectory file into a list of SE3State objects.
Each row in the file should have 8 entries separated by spaces with the
following format:
timestamp px py pz qx qy qz qw
where px, py, and pz are the position components of the robot pose,
and qx, qy, qz, and qw are the quaternion components of the robot pose
corresponding to the DCM C_ab.