Summary page at end of preprint submission process

[ketilog]

Is your feature request related to a problem? Please describe.
The submission process for preprints ends with a button "Step 3 of 3" for authors to click. This is a little abrupt and there is no way for authors to reviewer their submission before completing it.

Describe the solution you'd like
After clicking the button "Step 3 of 3" there should be a page summarising the submission for the authors and a clickable button at the bottom of the page which reads "Submit" as a final step.

Optionally, the summary page could allow authors to jump back in the submission process to edit parts of the submission. Definitely not a must, though.

Describe alternatives you've considered

Additional context

[alainna]

Flagging this one as request for 1.16