Add a 'Sign Out URI(s)' field to the 'Submit/Edit' app forms

[HollyJoyPhillips]

Summary: As we are now supporting Sign Out URIs in Cognito, we need to add an additional field on the ‘Submit’ and ‘Edit’ app page in the developers portal.

Task: To add a field on the ‘Submit’ and ‘Edit’ app pages in the developers portal.

• Title: Sign Out URI(s)
• Placeholder text: Enter the URI that your application should navigate to when a user logs out. For multiple URI's, separate using a comma. HTTPS other than for http://localhost
• Object: signoutUris
• Should be editable
• Should support multiple URIs separated by a comma, e.g. https://www.app.co.uk, http://www.app2.co.uk
• Should apply validation to ensure HTTPs is present and the URI format is correct (same as the Launch URL field)
• Should allow HTTP for local host only e.g. http://localhost:8080
  See mockup for location: