Approval: Re-review documents when policies change

Feature request: invoice workflow

When a policy is changed or added, please scan all unposted documents that are not in the Needs Approvals state (there may be other states) to see if we can assign one of the new policies to the documents. Right now the user has to do something very obscure and unexplained (modify the captured details) to get one of the new policies to take.

In general, updated policies should be applied to all documents. For exmaple, if the minimum amount is changed then simiarly the status should be changed.

Raised by BC