feat request: ability to restart a task via sonmcli

[nikonov1101]

Received feedback from the tech support chat. User wants to have a handle in CLI to restart their tasks.
Consider something like sonmcli task restart <deal_id> <task_id>, which should stop the given task, remember the task's image name, and then start a new task with that image.

Note to teammates: how to deal with tasks which resources were restricted by the task.yaml?

[3Hren]

Without the atomic guarantee, it can be a situation when you stop the task and there isn't possible to start it again with updated resources. So the only way to do this properly is inside the worker.

[nikonov1101]

Thanks for comments.
I'd mind to implement it as part of the worker, too. That must be more robust - we already have access to the docker API, thus can just restart existing container, moreover, we can keep same task ID which looks good at the user's point of view.