Add button STOP Burst and STOP Operation.

On Operations page add button STOP in the table view.
In the context of BURST, in case a burst is finished button X should remove entire data.
In case Burst is in progress, button X should stop working processes.

Currently we have PID for each operation started asynchronously. Should we store that in DB on Operations table? What will happen in case of concurrent operations? (worker and parent)?