ZFS allow send:encrypted

A new zfs allow permissions that ONLY allows sending replication
streams in raw (encrypted) mode, so encrypted data will not be
decrypted as part of the replication process.

Sponsored-by: Klara, Inc.
Sponsored-by: Karakun AG
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Co-authored-by: JT Pennington <jt.pennington@klarasystems.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes #17543