Minor consistency/order updates for menu items which reference other objects

Summary:
See T11957#208140.

• Let Applications have a custom name, like other object items (for example, so you can call Maniphest "Tasks" if you prefer).
• Put the optional name field after the required typeahead field for these items.
  • (I left "Link" in "Name, URI" order since both are required, but there's maybe an argument for swapping them?)

Test Plan:

• Created each type of item, saw "thing, name" order.
• Created an application with a cusotm name, saw custom name.
• Removed custom name, saw original name.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D17236