"Create New Ticket" UI should fit on one screen

[lashchev@…]

Since Trac is (successfully) pitching a minimalistic approach to task/bug management - "Create New Ticket" UI should be as simple as possible so it takes seconds for users to create new tickets/tasks.

To achieve this:

• Fields should take reasonable space (not like "Reporter" taking the whole UI line now)
• Required and/or typically used fields should be displayed on one-page screen (no scrolling to hit "Submit"/"Preview"). Other fields can be moved into a collapsable panel which is collapsed by default.
• Admin should be able to say what fields to display in "main" properties form and which ones to move to collapsed "advanced" panel. Custom fields should go to "advanced" panel by default unless otherwise specified during custom field install.
• Order of displayed fields should be consistent (ideally - configurable)

[osimons]

See also #7640, #7641.