Bug 15098: Itemtype description missing from facets for itypes in a search group

Bug 15098: Itemtype description missing from facets for itypes in a search group

This patch adds a second variable to hold item types info
just for facets.

In case we have an item type in a search category, it's description
is removed from GetItemTypesCategorized, which is good for advanced
search, but no for facets

A second var is needed which holds all item type info.

To test:
On top of Bug 15092 patches (no really needed, but I write this on top
of them)
1) Add an item type to a search group
2) Do a search in opac, in facets will see only item type code,
no description, for that item type
3) Apply the patch
4) Repeat search, now description must be present

Followed test plan including translated descriptions. Works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>