Detect more email header names that are likely to appear in messages

Fixes extracting email headers from messages in Sent folders in some cases.

Also reduces noise in the debugging logs in some instances.

Co-authored-by: Ivan Zakharyaschev <imz@altlinux.org>
Fixes: https://bugzilla.altlinux.org/show_bug.cgi?id=32430
Imported-from: https://git.altlinux.org/gears/l/libpst.git?p=libpst.git;a=blob;f=libpst-0.6.76-alt-known-fields.patch;h=b1e8d250b0bae7c44a9e5b62f280c24e086dd1af;hb=HEAD