Autosave improvements

[Macroz]

Autosave can be improved.

• change event text "Alice saved a draft." -> "Alice updated the application."
• "Application is saved." could include the time when it was saved
• in warnings for autosave, don't complain about empty fields (as they could be further down the page and not answered yet)
• a warning for a field is always shown with the red color, this should be yellow (this turns out to be difficult and likely also confusing)
• font-size seems to be too small for the field error, it's not the same as the other text
• when entering a draft / returned application (that has been saved), we could show the warning text, i.e. validate the application to show what is still not done
• split issue Validate DUO codes with /validate #3051