DS-2177: Batch Import via the UI (new features and improvements) - JSPUI

Related JIRA Issue: https://jira.duraspace.org/browse/DS-2177

UI support for batch import (Simple Archive Format + other bibliographic formats)

Features:

1) UI Batch import of Simple Archive Format zip file. 

2) Enhance the UI to support selection of multiple collections apart from the owning one 

3) Ability for the users to see their Batch Imports in the UI with the following functions: 

a) display the datetime of the import 
b) dislay if the import was successful or not 
c) download the corresponding mapfile 
d) ability to delete the import (all the corresponding files in server + the imported items themselves) 
e) ability to resume an old import (in case of error) and upload a new file 

This extension is build on top of PR: https://github.com/DSpace/DSpace/pull/650 (JIRA: DS-1933) thus, this PR's commits are a superset of the other PR's commits 
context.complete, means that the emailErrorMessage (on line 2393) won't have the context, so it will fail (NPE) when it looks up eperson.language.