[Kernel] Give metaboxes access to plugin creation through plugin manager
requested to merge gh-e958ce81/63/mensiatech/feature-jole-core360-access-plugin-manager-from-boxes into master
Created by: jlegeny
Tracker Reference: CORE-360
Warning: This branch is to be merged into master AFTER the CORE-359 branch was merged. This PR makes it possible to view the future diff to master.