Adds flags for ACU checking to hwp supervisor, along with tests

[jlashner]

Description

Motivation and Context

This adds gripper-state monitoring to the HWP monitor process, and adds the following flags to the HWP state which can be checked by the ACU:

• gripper_state which can be "cold", "warm", "ungripped", or "unknown"
• is_spinning boolean

How Has This Been Tested?

Along with these changes, I am building out the HWP emulator into a set of integration tests that test the behavior of these flags and other operations.

This has been tested with HWP and ACU hardware on satp1.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[jlashner]

@BrianJKoopman Ended up getting the tests to work properly! Turns out I missed a shutdown call for one of the device_emulators in the hwp emulator. Adding that makes tests clean up correctly, so I reverted the misc changes I made to test the github workflow.

This contains the same update to the HWP supervisor as #805, so if you'd rather just review and merge this one we can close the other one. Thanks!