Bug 7818: utility to generate DOM indexing configs

Bug 7818: utility to generate DOM indexing configs

misc/maintenance/make_zebra_dom_cfg_from_record_abs:
  generate a DOM filter Zebra index config from a GRS-1 config

Given a Zebra record.abs file containing a set of index definitions for
Zebra's GRS-1 filter, write an equivalent DOM filter configuration.

To generate the XSLT that is to be used by Zebra, run something like
the following on the output of this utility:

xsltproc ZEBRA_CFG_DIR/xsl/koha-indexdefs-to-zebra.xsl \
  biblio-koha-indexdefs.xml \
  > ZEBRA_CFG_DIR/marc_defs/marc21/biblios/biblio-zebra-indexdefs.xsl

The above example assumes that the output of the program was named
biblio-koha-indexdefs.xsl.

This commit also introduces Koha::Indexer::Utils, a new package for
misceallenous routines that support Koha's indexing definitions.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>