Add relative_direction function to Pose

[pascalzauberzeug]

I wanted to know how much the robot has to turn to face a target.
You first have to get the direction to the target and then calculate the difference between the direction and your robot's current yaw.
This PR combines this approach in the Pose.relative_direction(Point | Pose) function to make it more easily available.

@falkoschindler the angle parameter of rotate(self, angle: float) collides with rosys.helpers.angle. I imported it as helpers_angle for now, but I don't really like it.

[falkoschindler]

Thanks, @pascalzauberzeug!

I changed the import to from .. import helpers to avoid conflicts with angle without the need for an alias.

When reading the code, I wonder why we use @overload for distance(), direction() and relative_direction(). It might be useful in case where, e.g., the return type depends on the input type like here:

rosys/rosys/vision/calibration.py

Lines 181 to 187 in e071d80

	@overload
	def project_to_image(self, world_coordinates: Point3d) -> Point | None: ...
	@overload
	def project_to_image(self, world_coordinates: np.ndarray) -> np.ndarray: ...
	def project_to_image(self, world_coordinates: Point3d | np.ndarray) -> Point | None | np.ndarray:

or where we want to use a different docstring for each variant. But distance() always returns float and has no docstring, so I don't see a benefit over a simply union type annotation. Of course, this isn't really the point of this PR. It's just a related thought we could address here or in a subsequent PR.