The administration UI's Change Form, which is responsible for adding or

modifying objects in the database, is complex and has a lot of custom

JavaScript that can be fragile when we update our version of Django and

can interact poorly with our own logic and styling.
This change introduces the beginning of a view for managing the Change

Form, which currently just sets up the biggest part of this change, the

new Inline Forms classes.
Inline Forms are a Django admin UI concept that makes it easy to add or

modify related objects all in the same Change Form page.
This change provides custom code for managing these forms, allowing us

to control any initialization of form elements, maintain styles that

won't conflict with other parts of the page (unlike current inline

support), and check for regressions through unit tests.
This is a big chunk of the client-side work for this page, which is why

we're starting here. Upcoming changes will improve upon the styling and

component structure of the page.

JavaScript unit tests pass.
Tested the inline forms on several different models, verifying that

adding and removing work as expected and that state on the forms are

correct.