code: @RequestMapping(value = "{entityType}/{id}/{propertyTypeName}/view", method = RequestMethod.GET)
      public Resource<Property<?>> getPropertyValue(@PathVariable ProjectEntityType entityType, @PathVariable ID id, @PathVariable String propertyTypeName) {
          return Resource.of(
                  propertyService.getProperty(getEntity(entityType, id), propertyTypeName),
                  uri(on(getClass()).getPropertyValue(entityType, id, propertyTypeName))
          );
      }
docs: Gets the value for a given property for an entity. If the property is not set, a non-null
  {@link net.nemerosa.ontrack.model.structure.Property} is returned but is marked as
  {@linkplain net.nemerosa.ontrack.model.structure.Property#isEmpty() empty}.
  If the property is not opened for viewing, the call could be rejected with an
  authorization exception.
  
  @param entityType       Type of the entity to get the edition form for
  @param id               ID of the entity to get the edition form for
  @param propertyTypeName Fully qualified name of the property to get the form for
  @return A response that defines the property