Warn when updating OrderId and InvoiceId

[Jemt]

Warn user when updating Invoice ID, which may have consequences in regards to book keeping.
Also warn if Order ID is updated, which on XML based data sources may break optimizations for XML Archiving since we keep track of order IDs known to be available in "current data".
So switching Order ID from e.g. 1000000 back to 1000 will cause all orders to be queried from the archive which is painfully slow.