Allow resubmitting rejected webform submissions

Resubmission lets a user create a brand new submission pre-filled with the values of an existing one, picking up where the old submission left off (e.g. after it was rejected) rather than editing the rejected submission directly. 

The new submission is linked back to the original so both can be traced, and any log messages left on the original (e.g. the reason it was rejected) are shown to the resubmitter.

Enabling resubmission for a workflow state

1. Edit the workflow element and open the settings for the relevant state (e.g. "Rejected").
2. Tick "Allow resubmission from this state".
3. Save the element/workflow settings.

Anyone who has access to create a new submission on the webform can now resubmit a submission that is sitting in that state - there is no separate permission for resubmission itself.

What the user sees and does

1. While viewing a submission that is in a state with resubmission enabled, the user sees a "Resubmit" button.
2. Clicking it takes them to a new, blank submission form for the same webform, with all the original field values pre-filled.
3. A notice at the top of the form says "This is a resubmission of submission #X", linking back to the original. Any user-facing log notes from the original (e.g. the rejection reason) are listed underneath, so the user knows what to fix.
4. Near the submit button there is an optional "Resubmission note" field where the user can describe what they changed.
5. When the user submits the form, the new submission is created and its workflow is reset to the initial state (e.g. "Submitted") - it goes back through the workflow as if it were a fresh submission.

What happens on save

• The new submission stores a link back to the original and the optional note.
• The original submission is logged as "Superseded by submission #Y".
• Viewing the original submission now shows a notice that it has been superseded, linking to the new submission.
• Viewing the new submission shows the "this is a resubmission of #X" notice (with the note and any public log messages from the original), so reviewers can see the history.

Cloning

Separately, any submission can be cloned via a "Clone" button (no workflow state restrictions - available to anyone who can view the submission and create new ones). 

This works the same way as resubmit (pre-fills a new submission and links the two together via lineage notices), but doesn't show log notes and doesn't require the webform to use workflows at all.