DS-1360 Porting advanced embargo function to JSPUI

https://jira.duraspace.org/browse/DS-1360

A new rebased version for the jspui advanced embargo porting made by zuki
previous PR #235

- changed the configuration parameter from xmlui.xxxxx to webui.xxxx so to have a single uniform configuration for both UI
- fixed some minor issue in advanced form after have configurated an embargo policy  (the first one was always proposed as default for new policy)

I will left this PR open for some days to allow other to jump in and help with the following improvement: when the JSPUploadWithEmbargoStep is used the bitstream policy eventually inherited from the embargo policy on the item level coming from the JSPAccessStep are not shown and the user is required to make a further click on the access policy button. On the other side if the JSPAccessStep is not enabled the user need to click on the access policy button in the review upload screen to actually set the embargo.
IMHO it will be better if, when the embargo is enabled, after the upload the user will be automatically redirect to the bitstream policy definition.