Separates setters inside Articulation for joint position and velocity

[Mayankm96]

Description

Previously in the Articulation class, there was a single method for setting joint state. However, it is desirable at times to only set joint position or velocity. For instance, for randomization events that pushes a joint by adding a random velocity to it.

This MR separates the write_joint_state_to_sim into separate setters for joint positions and joint velocities. This goes inline with the method to set root pose, root velocity or the root state.

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 NITs on units

[jtigue-bdai]

Suggested change

	velocity: Joint velocities. Shape is (len(env_ids), len(joint_ids)).
	velocity: Joint velocities (rad/s). Shape is (len(env_ids), len(joint_ids)).

[Mayankm96]

Velocities are rad/s for revolute and m/s for prismatic?

[jtigue-bdai]

Suggested change

	position: Joint positions. Shape is (len(env_ids), len(joint_ids)).
	position: Joint positions (rad). Shape is (len(env_ids), len(joint_ids)).

[zoctipus]

I found some reference in Physx about joint units hope this is useful!