Bug 16735: Migrate library search groups into the new hierarchical groups

Bug 16735: Migrate library search groups into the new hierarchical groups

Test Plan:
1) Apply this patch set
2) Note your existing search groups have been ported over to the new
   __SEARCH_GROUPS__ group if you had any
3) Create the group __SEARCH_GROUPS__ if one does not already exist
4) Add some first level subgroups to this group, add libraries to those groups
5) Search the library group searching in the intranet and opac
6) Note you get the same results as pre-patch

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>