Add link to Submit New Job after submission

Requested here: https://wordpress.org/support/topic/go-back-to-create-a-job-offer/

We could add a link to https://github.com/Automattic/WP-Job-Manager/blob/master/templates/job-submitted.php which says something like "Submit another job here" or something.

Open templates/job-submitted.php and inspect the markup shown after a job is submitted. Add a link with wording such as “Submit another job here” that leads back to the job submission flow. Done means the link appears on the successful submission page and takes users to the form.

Written by the indexing model from the issue text.