Add new fields to deployment schedule forms in the UI

[abrookins]

Add new fields to the deployment schedule create and edit forms:

1. max_active_runs (int, default unset/null)
2. max_scheduled_runs (int, default unset/null, max 50)
3. catchup (bool, default true)

Notes on behavior:

1. Client-side validation should show errors on the form
2. Submitting the form and receiving an error response should show an error on the form.
3. Closing the form with an error displayed (either client- or server-side generated) and reopening it should clear the fields and the error