Description:

Options to control cyr_expire's mailbox cleanup behaviour.


Config changes:

Adds two config options:

1) expire_by_savedate (default false)

If set, check the savedate rather than gmtime on records to decide
whether to expunge them

2) expire_keep_flagged (default false)

If set, never expunge messages with the \Flagged system flag set.


Upgrade instructions:

No change required.


GitHub issue:

No issue
