xmlui: Add XMLUI theme for CIAT

Initial commit.  Contributed by Sisay Webshet.
xmlui: Sync CIAT theme assests with DSpace 3.1 Mirage

Missing images, old JavaScript, etc.
xmlui: Remove some unneeded images from CIAT theme
xmlui: Clean up CIAT banner configuration
xmlui: Add bits for Atmire reports to CIAT theme
xmlui: Various updates to CIAT theme XSL
xmlui: Update CIAT theme for enhanced thumbnails
xmlui: Remove unneeded image from CIAT theme
xmlui: Update XSL stack for CIAT theme
xmlui: More cleanups to CIAT theme XSL

Style, cruft, etc...
Merge branch '3_x-dev-ciat' into 3_x-dev-next
xmlui: Update CIAT theme CSS

Sync a bit more with branding on CIAT website.
Merge branch '3_x-dev-ciat' into 3_x-dev-next