add SpawnBoxCollider func

[KuoHaoZeng]

The newly added SpawnBoxCollider function generates a box with an active collider encapsulates the agent. Currently, it only supports the Stretch agent.

New augments:

1. useFPINCollider: bool. When set to True, SpawnBoxCollider is included during the initialization phase. If False, initialization proceeds as previously.
2. colliderScaleRatio: dict. It specifies the scale ratio of the box along each axis, for example, {"x": 1.0, "y": 1.0, "z": 1.0}. A value of 1.0 indicates that the box size matches the detected bounds.

[KuoHaoZeng]

Update

• Merged from physics-det-new-cam-adjust with code refactors.

• I added UpdateAgentBoxCollider with an argument colliderScaleRatio=vector3 to spawn a new box collider. It will spawn a box collider according to agent's body (after destroy the pre-existing one)

• On the other hand, DestroyAgentBoxCollider will just removes the existing box collider.

• No UseFPINCollider augment anymore!

• Nothing happens with box collider functionality anymore during the initialization or reset.

• To adjust the collider, we must explicitly call UpdateAgentBoxCollider or DestroyAgentBoxCollider

• Add imageSynthesis.OnCameraChange() at the end of updateCameraProperties to solve the segmentation mask issue with the change of FoV.

[AlvaroHG]

Nothing jumps out, and looks good. But what I recommend to make sure things work as expected, and easier for the reviewers to understand how the code should work is creating some unit tests :) LGTM after some minor comments