Adds configuration classes for spawning different assets at prim paths

[Mayankm96]

Description

This MR adds configuration classes that allow spawning different assets at the resolved prim paths. For instance, for the prim path expression "/World/envs/env_.*/Object", these configuration instances allow spawning a different type of prim at individual path locations.

Fixes #186

Type of change

• New feature (non-breaking change which adds functionality)

Checklist

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

[jtigue-bdai]

Just some minor docstring stuff. LGTM

[renezurbruegg]

Thanks a lot for implementing this!

In my experience, spawning multiple can lead to quite some issues when replicate physics is set to true, especially if additional randomization are applied. Could be helpful to add a check if replicate physics is set and a MultiAsset spawner is used, and if yes, print a warning?

[Mayankm96]

Thanks a lot for implementing this!

In my experience, spawning multiple can lead to quite some issues when replicate physics is set to true, especially if additional randomization are applied. Could be helpful to add a check if replicate physics is set and a MultiAsset spawner is used, and if yes, print a warning?

@Dhoeller19 What do you think? I added a note in the how-to but of course not the best (since many might miss it).

One solution could be: We set a carb flag that multiple assets were spawned (the flag is set inside the spawner function). And then in the environment we check if this flag is True and replicate physics is True, and throw a warning accordingly?

[Mayankm96]

@renezurbruegg @Dhoeller19 Added a check inside InteractiveScene.