oc: Guess recipients from some properties while importing PST

This is happening when importing a PST file.

From -> PidTagSenderEntryId
To   -> PidTagOriginalDisplayTo
CC   -> PidTagOriginalDisplayCc

The tested EntryID are the local users and OneOffEntries
when the users are not from the directory.

It requires https://github.com/openchange/openchange/pull/175 to work.