Bug 20702: Bind results of GetHostItemsInfo to the EasyAnalyticalRecords pref

Bug 20702: Bind results of GetHostItemsInfo to the EasyAnalyticalRecords pref

Triggered by the finding on bug 20697.
The three calls of GetHostItemsInfo should be controlled by the pref. This
patch makes the sub return an empty list when the pref is disabled.

The patch simplifies the sub by merging the two identical foreach loops
depending on the field number in MARC21/UNIMARC.

Will add a unit test on a follow-up patch.

Test plan:
See next patch.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>