Depends on DS-3540.
The new Angular UI already has basic support for Google Analytics. However, currently the analytics key must be duplicated into the Angular UI configuration file (see https://github.com/DSpace/dspace-angular/issues/244)
Instead, the REST API should expose this information on a configuration endpoint (see DS-3540), so that the backend and frontend can share the same analytics key. (NOTE: the backend also needs the analytics key to track bitstream downloads & send those to GA, as those must be done in Java code.)