Need Restart task for hwp-encoder and hwp-gripper

[ykyohei]

We have recently added a "restart" task to the hwp-encoder and hwp-gripper agents, this task will restart the process running in the beagle bone (simonsobs/socs#738, simonsobs/socs#737).
It is really helpful to have buttons for this task in OCS-web.

[mhasself]

Those agents don't have customized panels, and those new tasks don't take any params. So it is likely that auto-population is all you need, and that should occur correctly as soon as the new versions of the agents are running. So I don't think any ocs-web code changes are needed.