Ability to update/reorder/skip deployment steps before running/resuming

[mmooney]

Once a deployment has been requested, the steps cannot be changed without creating a new request. However, often times the steps are requested out of order, or a step fails and we want to skip that problematic step to complete the rest of the deployment. We need to add some UI functionality to approve/begin/resume flow to edit the steps that will be run and skip steps if necessary.