Author: David Carrillo
MDL-86065 customfield: Allow to select shared categories on each entity
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a0001c8776b648b38aa317da422b823bbcbf4eb5
http://github.com/moodle/moodle/commit/a0001c8776b648b38aa317da422b823bbcbf4eb5
+ 5.1 en [eventsharedcategoryusagedisabled,core_customfield]
+ 5.1 en [eventsharedcategoryusageenabled,core_customfield]
+ 5.1 en [sharedcategoryhelptext,core_customfield]