Add tags for night and freshwater

Also trim the redundant "Dive" text from "Lake Dive", "Pool Dive", ....

Signed-off-by: Henrik Brautaset Aronsen <subsurface@henrik.synth.no>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Automatically show Freshwater tag (but don't set it)

If the salinity is 10000 we show (but do not set) the Freshwater tag.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>