Bug 27680: Add support for sorting fields with multiple data points

Bug 27680: Add support for sorting fields with multiple data points

This patch adds proper handling for sorting a single column that is
constructed of multiple data entities.. i.e `"data": "string1:string2"`

It does NOT add support for filtering on multiple columns yet.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit fa1671aba529e55f124eb759f3b09e237a7282fe)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>