Bug 27798: Add warning to IndependentBranches system preference

Bug 27798: Add warning to IndependentBranches system preference

Test Plan:
1) Apply this patch
2) Search system preferences for IndependentBranches
3) Note the warning about changing the setting on a production system

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
JD Amended patch:
* Fix commit title
* Don't split the syspref's description, otherwise the sentence will be
split in the POs

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit fa8a60ddc8ac45404b6159fde5c758e4b0dad60b)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit 934e033496d3774edf2522aa1f8d140eb2f0af45)

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>