feat: add a method to restart a single service

[masci]

Since workflows have a handy cancel_run method, it would be useful to provide a similar functionality at the apiserver level. Restarting a workflow service would cancel the underlying workflow run, achieving the same goal.

[abdulhuq-cimulate]

@masci A workflow service could potentially be running multiple workflow runs, what if we want to cancel a single workflow run using the workflow run id or the task id?