Continue-as-new support

[kaibocai]

The SDK should support continue-as-new pattern for orchestration.

end-to-end example

  it("should allow to continue as new", async () => {
    const orchestrator: TOrchestrator = async function* (ctx: OrchestrationContext, input: number): any {
      if (input < 10) {
        ctx.continueAsNew(input + 1, true);
      } else {
        return input;
      }
    };

    taskHubWorker.addOrchestrator(orchestrator);
    await taskHubWorker.start();

    const id = await taskHubClient.scheduleNewOrchestration(orchestrator, 1);

    const state = await taskHubClient.waitForOrchestrationCompletion(id, undefined, 30);
    expect(state);
    expect(state?.runtimeStatus).toEqual(OrchestrationStatus.ORCHESTRATION_STATUS_COMPLETED);
    expect(state?.serializedOutput).toEqual(10);
  }, 31000);

Tested failed on local

Reference: #4