Remove refences to blacklist/whitelist

These terms reinforce the incorrect notion that black is bad and white
is good.

Replace this language with more specific terms which are also more clear
and don't rely on metaphor. Specifically:

• When vdevs are specified on the command line, they are the "selected"

vdevs.

• Entries in /dev/ which should not be considered as possible disks are

"excluded" devices.

Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10457