Initial changes for Anancy -> CTA

Anancy is one of many projects in CTA, so lets be a bit better about
naming their stuff appropriately.
xmlui: Rename Anancy theme to CTA
xmlui: Finish rename of Anancy -> CTA
xmlui.xconf: Use CTA theme instead of Anancy
input-forms.xml: Change Anancy -> CTA

CTA is the parent organization for Anancy, so this is more accurate.
messages.xml: Anancy -> CTA
xmlui: Update CTA theme for thumbnail rework
xmlui: Use CTA subject in item list