[DSpace 7 Upgrade] Reimplement extension RestrictedItemsTransformer customizations

[wwelling]

Blocked by https://github.com/TAMULib/tl_docker/issues/93 due to lack of dynamic eperson groups.

Research and propose an implementation for a future issue.

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https://github.com/TAMULib/DSpace/blame/tamu-dspace-6.3/dspace/modules/xmlui/src/main/java/org/tamu/dspace/extensions/RestrictedItemsTransformer.java

Unfortunately, our customizations in this file are not noted with the generally used "TAMU Customization" comment.

The purpose of this customization is to add informative language to the page when items have restricted access. When off campus, it will tell people to use VPN or a campus IP to see the bitstreams that are on-campus only. It will also provide proper messaging when bitstreams are admin only.

Check dspace/modules/xmlui-mirage2/src/main/webapp/themes/Mirage2/xsl/core/page-structure.xsl to see the custom text that gets invoked in the different cases.

Note - the language will need to be changed as well. TS does not want us relying on VPN anymore as the primary way for users to access restricted documents. So, wherever it says to use VPN, have it say instead to log in via EzProxy http://ezproxy.library.tamu.edu/login

[wwelling]

This issue may require an additional issue for dspace-angular. Or possibly transferred if no changes required in DSpace.

[jsavell]

After taking a look, in this case the entire file and feature is a TAMU extension implementation in our own namespace, so we weren't overlaying/customizing any upstream files.

I'm not sure what the equivalent of that manakin extensions approach will look like in 7 and how it might be split between api and angular.