rename HAMode to HighAvailabilityMode, and same for priority
(this brings us in line with convention on treatment of abbrs being camel case,
preferring HttpRestApi over HTTPRESTAPI, but without the weirdness of HaMode; easy enough to be explicit on this API, imho)
increase the brooklyn node poll frequency to every 2s, to prevent saturating it with monitoring, and other minor tunings to BrooklynNode