Add a new package to autoware.universe common that manages Trajectory

[yhisaki]

I created Trajectory class in autoware_motion_utils.
This class provides a new way of manipulating trajectory, and will alternate current motion_utils's functions.

Currently, these classes is implemented in autoware_motion_utils. However I think this class should be implemented in different package from autoware_motion_utils.
The reasons are listed below.

1. Trajectory has no dependencies with other programs in autoware_motion_utils.
2. Trajectory's code is too large.
3. Namespace can be shortened by removing ::motion_utils::.

I created PR about this.

autowarefoundation/autoware.universe#9253

If you have an opinion on this, please let us know.