Properly style new-thing entry form page

[jdickey]

This includes things like some sort of title/header and decent-looking layout for the form. What we have as of Commit a486e72 is functional, but that's it. "Enhancement" because it's not technically a bug, even though usability is adversely impacted by the status quo. When and if the second such issue is opened, perhaps a usability label ought to be added.

[jdickey]

This is distinct from Issue #6 only in that it mentions adding content to the new-thing entry form page. Closing it as duplicate of #6 for that reason, and will modify #6 to mention adding a title to the form page. 😜