This implemented support for having multiple datasets unlocked and
mounted when a session is opened.
Example: `homes=rpool/home,tank/users`
Extra unit tests have been added
A man page documents have been added `man 8 pam_zfs_key`. A few
references to the new man page have also been added in other documents.
Signed-off-by: Dennis Vestergaard Værum <github@varum.dk>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
