DS-1360 Porting advanced embargo function to JSPUI

https://jira.duraspace.org/browse/DS-1360

This pull request is only a rebase of #116 against current master to squash it and remove an unwanted change to build.properties (this one: https://github.com/zuki/DSpace/commit/25f50b9d3d0bdd6755b75d91927c9af972b2d992).

I only tested whether it builds, not whether it works.