Bug #2754 Show hold request priority in OPAC

Bug #2754 Show hold request priority in OPAC

Code changes to display the priority level on holds in OPAC. Turned on/off based on System Preference.  Database changes to systempreferences for both English and French

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>
Fixed to work with 3.0.4

Conflicts:

	admin/systempreferences.pl
	installer/data/mysql/en/mandatory/sysprefs.sql
	installer/data/mysql/fr-FR/1-Obligatoire/unimarc_standard_systemprefs.sql