RBAC for Forms Workflow Transition Buttons

It would be very helpful if we had role based access control for the transition buttons of forms. This is quite important as at the moment you can only restrict the use of a transition button based on permissions.

This means that if a user has a role which includes approve permissions for example then they can use every transition button that is restricted to users who have approve permissions. This creates a problem though because there could be many different forms on a project and they can have different sets of people who should be approving for example. One user should be an approver for Form A but should not be for Form B and C.

An easy solution for this would be the ability to restrict the use of a transition button to a role instead of general permissions. This way we can have multiple sets of approvers for example and we can make sure that users can only use a transition they should.

The statuses of form workflows already have this capability, with a feature to make a status only visible to a certain role, so hopefully it will be an easy feature to implement for the transitions as well.