As a user, I want to create an app using all fields in its definition from the GUI.
Currently the app modal does not expose all the fields available in the API. This means that a user cannot, for example, specify forcePullImage=true on a docker application.
The modal would become very unwieldy if all fields were available to be edited. We should therefore provide an advanced mode which allows the user to deal directly with the JSON app definition.
- a tab allows the user to switch between the form and the JSON editor
- switching between the two tabs preserves the latest edits in either mode
- the editor need only check for JSON validity