Remove MARC tags during record import

[Bill Erickson]

This is a patch to support the following... (from the release notes):

Administrators can configure MARC tags which are removed from MARC records imported via Z39.50 and the Vandelay MARC Import/Export UI (ACQ and non-ACQ). Tags are organized into groups. Groups can be marked as optional or required. For each tag, every instance of the tag (including all subfields) are removed from the record.

MARC fields which are contained within required ('always_apply') tag groups are always removed from inbound records. No action is needed. Tag groups which are optional will appear in MARC import interfaces (see below) allowing staff to select which groups of tags to strip from incoming records at import time.

Interfaces Affected
-------------------

* Admin UI
 ** Admin => Server Administration => MARC Import Remove Fields
* Z39.50 Import
 ** Cataloging => Import Record from Z39.50
 ** Optional groups appear with the other import options
* Vandelay
 ** Cataloging => MARC Import/ExportVandelay
 ** Acquisistions => Load Order Records
 ** Optional groups appear with the other import options

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Code lives at working => user/berick/marc-import-strip-tags

[Mike Rylander (mrylander)]

Thanks, Bill. Merged to master.