Allow EditEngine create and edit forms to be reordered

Summary:
Ref T9132. Ref T9908. Puts reordering UI in place:

• For create forms, this just lets you pick a UI display order other than alphabetical. Seems nice to have.
• For edit forms, this lets you create a hierarchy of advanced-to-basic forms and give them different visibility policies, if you want.

Test Plan:
{F1017842}

• Verified that "Edit Thing" now takes me to the highest-ranked edit form.
• Verified that create menu and quick create menu reflect application order.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9132, T9908

Differential Revision: https://secure.phabricator.com/D14704