Add Theme to Carrion Exhibition

[kelea99]

Summary

Following lead from closed ticket "when we have need". We have need of this feature for carrion. Kim McCauley has concrete example of what she and the curators want to enhance the site she is building.
#872

Impact

Please include hard deadlines, if the exhibit is part of an event, the issue is stopping work, etc.

Priority recommendation

• asap
• within the next 3 weeks
• PO will prioritize

Sudden Priority Justification

Required if "asap" or "within the next 3 weeks" is checked. Add "Sudden Priority" and "Maintenance/Research labels

Expected behaviour

Actual behaviour

Steps to reproduce behaviour

Screenshots