Bug 28373: [21.05.x] Add PassItemMarcToXSLT system preference

Bug 28373: [21.05.x] Add PassItemMarcToXSLT system preference

Default stylesheets do not reference item fields for XSLT display, however, we
spend time translating the values in the item fields.

This patch adds a system preference, PassItemMarcToXSLT. and unless enabled we remove
item fields before processing

To test:
1 - Perform some search on the staff client and opac
2 - Use the console (F12) to view the time spent on the network tab
3 - Note performance
4 - Apply patch, updatedatabase, restart_all
5 - Repeat searches
6 - Note that display has not changed
7 - Note performance, results should display slightly faster

Signed-off-by: Emmi Takkinen <emmi.takkinen@koha-suomi.fi>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Bug 28373: Unit test

Signed-off-by: Emmi Takkinen <emmi.takkinen@koha-suomi.fi>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Bug 28373: (QA follow-up) Fix typo in system preference description

Signed-off-by: Emmi Takkinen <emmi.takkinen@koha-suomi.fi>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Bug 28373: (follow-up) QA fixes

Use fully qualified subroutine name
Don't return explicit undef

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Bug 28373: (QA follow-up) Add . to end of system preference description

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Bug 28373: Add note to XSLT prefs about the new pref

Bug 28373: Add warning if custom stylesheets are defined

This patch adds a check of the current XSLT prefs and warns to check the new pref
if any are not set to default

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>