instructions for how to add new global status

In pre 4.0 versions, adding new statuses was documented well enough with

http://bestpractical.com/docs/rt/3.8/RT_Config.html#ActiveStatus-InactiveStatus

but with lifecycles this is no longer valid and there is no documentation
on how to achieve this.
Merge branch '4.0/new-status-pod' into 4.0-trunk