[FR] Custom case closed state

[lukerosser]

Is your feature request related to a problem? Please describe.
Being able to add custom case state helps with reporting and tracking of where a case is up to when open. However it's also helpful to have different closed states to track why a case closed. Closing a case only allows the "Closed" state, you can't use any custom state to flag a case as closed.

Describe the solution you'd like
Give the option to add a type to custom case states to identify whether the case is open or closed when in that state.