For consistency (we don't call it EpsilonDP or EpsilonDeltaDP)). ZeroConcentratedDP could also work but feels a bit verbose, so ZCDP seems reasonable. @Maegereg what do you think?

We need the change to not break people immediately, so let's make RhoZCDP an alias that prints a deprecation warning if people try to use it (so people immediately know what to fix), and only remove it once we shipped one major release.