Introduced property com.openexchange.imap.namespacePerUser to file 'imap.properties'.

Description:
This option controls whether there it is expected to have a dedicated NAMESPACE per user or not. In case of true each mailbox account on associated IMAP server is allowed to have its own NAMESPACE set; might be (root) or INBOX.. Otherwise for false every mailbox is assumed to have the same NAMESPACE set.

This influences the way Open-Xchange Server detects & caches NAMESPACE information; either on a per user basis (more IMAP traffic) or globally (only requested once).

It should not be changed/touched unless IMAP server behavior is well know.

Default is true