[global_planner/orientation_filter] Add a mode deciding Forward/Backward automatically

[ssr-yuki]

Hi. I would like to propose a new orientation mode of global_planner.

Generally, we cannot determine whether Forward mode or Backward mode is optimal until we know a planned path, and the selected mode sometimes yields wasted rotational motion as a result.

To tackle this problem, I have implemented AUTOMATIC mode that selects optimal one (Forward or Backward) with simple algorithms: this mode just selects a mode minimizing (\alpha + \beta), the total rotation angle to align. \alpha and \beta are rotation angles at the initial position and the goal position, respectively (see the following figure).

Can I send a PR of this? Any comments are welcome. You can see the implemented codes here. Thank you.