LP1185524 - Duplicate patron checking in the user editor is limited to workstation OU

Added a new library setting opac.duplicate_patron_check_use_consortium.
When true, the duplicate check will use the consortium (1) as the OU.
When false or not set, the duplicate check will use the workstation OU.

The setting is checked in subroutine that creates the search request and
sets the OU accordingly.

[LFW: Signing off but following with material changes next commit.]

Signed-off-by: Kyle Tomita <ktomita@catalystitservices.com>
Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>
Adjust Kyle Tomita's patron dupe check fix to use the depth concept

Addressing these comments:
https://bugs.launchpad.net/evergreen/+bug/1185524/comments/3

And also renaming the OU setting to better peer with similar settings
affecting staff client (not OPAC) patron registration.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>
DB numbering for patron duplication check depth setting

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>