Add the OpenURL resolver caching service as an optional component

Add the OpenURL resolver caching service as an optional component

Currently limited to supporting the Ex Libris SFX OpenURL resolver,
this caches the results of looking up full-text availability of
resources by ISBN or ISSN.

For an example of incorporating this service into your OPAC, see
http://svn.open-ils.org/trac/ILS-Contrib/browser/conifer/branches/rel_1_6_1/web/opac/skin/lul/xml/result/result_table.xml#L102
for returning the full-text availability of a given resource by ISSN.

git-svn-id: svn://svn.open-ils.org/ILS/trunk@18666 dcc99617-32d9-48b4-a31d-7c20da2025e4