HITL - Add object visbility handling and hide "self" in viewports.

[0mdc]

Motivation and Context

This leverages instance metadata keyframes to hide objects in viewports.

It introduces the concept of "visibility layers".

• Objects are assigned to a visibility layer.
• Viewports are assigned a list of visibility layers.
  • All objects from these layers will be visible.

This also changes rearrange_v2 such as the user's agent is hidden from the first person view.

Notes

Depends on:

• Latest habitat-sim
• https://github.com/0mdc/siro_hitl_unity_client/pull/28
• https://github.com/0mdc/siro_hitl_unity_client/pull/29
• https://github.com/facebookresearch/habitat-lab/pull/1958

Agents are now transparent to selection, so they won't be interfering with UI flow:

• https://github.com/facebookresearch/habitat-lab/pull/1950

Examples

Before:

https://github.com/facebookresearch/habitat-lab/assets/110583667/7834dd94-b1a8-4147-8c80-b325d37c9118

After:

https://github.com/facebookresearch/habitat-lab/assets/110583667/7b0e4c6f-168e-4620-bde3-00c57b6f97e6

How Has This Been Tested

Tested on multiplayer HITL.

Types of changes

• [Development]

Checklist

• [x] My code follows the code style of this project.
• [x] I have updated the documentation if required.
• [x] I have read the CONTRIBUTING document.
• [x] I have completed my CLA (see CONTRIBUTING)
• [x] I have added tests to cover my changes if required.