Allow user to edit the builder before submit.

In a discussion with @mikibonacci and @unkcpz, we think we may provide an additional step before submitting the jobs for advanced users who want to override some settings not provided in the GUI.

## Idea
After step 3 (computational resource), we add step 4 (review and submit); in this step, we add a button ("inspect builder") to open the builder in a yaml file so that the user can edit and submit it.