title: User prompt for downstream job
body: <p>I would have <strong>job1</strong> with one dropdown parameter - ENV (DEV, QA, etc) which run and download some files from git repo, and after this it should run <strong>job2</strong> which has several another parameters that would be filled via Extended Choise Plugin from downloaded files during <strong>job1</strong>.</p>
  
  <p>And this <strong>job2</strong> should wait for user to check/edit default values of these parameters. </p>
  
  <p>And after setting all parameters user can press Build button to start building.
  I don't need to auto-run job2 because I need user to see all the parameters from job1.</p>
  
  <p>Is it possible in Jenkins?</p>