mutation to restart workflows with newer Cylc versions

[oliver-sanders]

Add wrapper-script aware mutation for auto-restarting workflows using newer versions of Cylc.

This is intended to make the management of long-running workflows easier by reducing the effort of upgrading to newer versions.

Note that cylc-flow already has the faculty for auto-restarting workflows so it would probably be better/safer to implement this there.

At the UIS end we would need functionality for listing Cylc versions, and some way of flagging to the UI workflows which are running using older versions of Cylc.

Pull requests welcome!