Reorganizes the structure to drop `omni.isaac` and directly use `isaaclab` as extension name

[pascal-roth]

Description

Reorganize the extensions to achieve a simpler and easier-to-understand structure. We make use of Kit 106, which drops the requirement to have the extension name as a composition of at least two elements separated by a dot and instead allows for a single word as name. Consequently, the extensions are renamed as follows:

• omni.isaac.lab --> isaaclab
• omni.isaac.lab_tasks --> isaaclab_tasks
• omni.isaac.lab_assets --> isaaclab_assets

This reduces the structure from omni.isaac.lab/omni/isaac/lab to isaaclab/isaaclab.

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Screenshots

While extensions can still be found as expected

Checklist

• [x] I have run the pre-commit checks with ./isaaclab.sh --format
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have run all the tests with ./isaaclab.sh --test and they pass
• [ ] I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• [x] I have added my name to the CONTRIBUTORS.md or my name already exists there

[Mayankm96]

Does this also work with Isaac Sim 2023.1.1? Just wondering if Kit 105.1 already supported a single extension name. Otherwise, this change also means a drop in support for 2023.1.1.

[pascal-roth]

@Mayankm96 I can test it but are we backward compatible in general so far with the code changes?

[pascal-roth]

also after merging #617 and #616 (introducing a Velodyne lidar and zed depth cameras), a further split of the assets into robots and sensors necessary

[Mayankm96]

@pascal-roth We discussed this internally, and Isaac Sim will change its extension naming following a style similar to the above in November. We have received push-back to do this change as it will break the user's experience twice (once now and again in November when Isaac Sim breaks the APIs). Hence, we have also decided to do this in November with Isaac Sim.

[pascal-roth]

There is no need for a review now; will be addressed in November when IsaacSim will also be renamed. Keep the PR open as information.

[pascal-roth]

closed for now, will be picked up in the new release