Bug 5959: Add search link for analytics to serial records

Bug 5959: Add search link for analytics to serial records

This will work similar to 'Show volumes' links from traced series records and
set records. A link to search for analytics linked to serials.

A new syspref will be added: UseControlNumber.

This syspref will make it possible to determine, if $w and Controlnumber are
used for linking of records in bibliographic records.

If syspref is OFF (default), the search links will not use control numbers
but keywords.
If syspref is ON links will be built using Control-number and rcn index.

NOTE: 773$a is added to index Host-item. For testing on a dev installation:
copy record.abs to your koha-dev folder and reindex!

Rebased against 3.03.00.035 and a small typo fixed by Jared Camins-Esakov.

Signed-off-by: Jared Camins-Esakov <jcamins@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>