Bug 24103: Add option to dump search query to templates

Bug 24103: Add option to dump search query to templates

To test:
1 - Apply patch, update database
2 - Note new syspref 'DumpSearchQueryTemplate'
3 - Leave it off
4 - Enable DumpTemplateVariablesOpac and Staff
5 - Search on staff and opac
6 - View the source
7 - Search for 'search_query' - you shouldn't find it
8 - Enable the new pref
9 - Repeat, but you should find the query
10 - Test staff/opac search and advanced search, cataloguing search, authority search, authfinder search, adding to a basket form a new biblio
11 - All should work and show the query
12 - This will work under both ES and Zebra

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>