DS-1917 JSPUI validity fixes (several non-controversial fixes)
edited for junii2 version 3.1
DS-1945 New override property request.item.helpdesk.override to have all email requests sent to the helpdesk instead of the item submitter
DS-1945 refactor to move code into dspace-api
Add RequestItemHelpdeskStrategy, that can be enabled with Spring DI

Cleans up Sam's "hard coded" approach
DS-1945 RequestItem Helpdesk has options to contact requester, and author
DS-1945 Add request_message to requestitem DB table

Also, refactored requestitem to be a dspace-api "model", moved all DB logic
from XMLUI regarding this module to the dspace-api model.

Add the requestitem.request_message to display in the contact-author form,
so they can see what the original request message was.
DS-1945 Add license headers for requestitem changes
Restricted Item request form, add link to login page for members
For request-item move the you can login Button before the request item para
DS-740 Allow media filter to set public-read permissions on thumbnails
DS-740 default the public thumbnails of restricted objects to off
Bugfix for DS-2012: commit after login to store last_active field.
DS-1994: Use HTML5 to upload files in Submission Process of JSPUI.
Use html5 upload only if supported by the browser. Fallback is default.

The old upload should be the default upload. HTML5 upload should be used
only if it is supported by the browser. This commits repairs the use of
the old upload and makes it the default.

A severe bug was found and fixed by this commit: The first version of
this feature was not thread safe as it used a instance variable were it
shouldn't. This commit fixes this bad behavior.

The message to inform the user, that its browser does not support
enhanced upload can be translated now.
Merge pull request #553 from tuub/DS-2012

Bugfix for DS-2012: commit after login to store last_active field.
Merge pull request #551 from tuub/DS-1994

DS-1994: Use HTML5 to upload files in Submission Process of JSPUI.
DS-2093: Remove dependency of dspace-api on backport-util-concurrent.
Merge pull request #594 from tuub/DS-2093

DS-2093: Remove dependency of dspace-api on backport-util-concurrent.
Adds configuration property for DS-1994.