#2286773 by cafuego: Allow connections with only a single entity.
#2211215 by gcb: Only show redhen user link message to CRM users.
#1962540: American date hardcoded.
#2313361 by levelos: Implement hook_entity_delete() to delete engagements associated with a deleted entity.
#2286063 by levelos: Add missing entity metadata getters and setters in RedhenNoteMetadataController.
Coding standards.