Default listen address values are not IPv6 friendly

[craigcabrey]

In at least three of the client charts (lighthouse, besu, and nethermind), the default listen address is 0.0.0.0. This causes issues for single stack (or IPv6-first dual stack) environments.

The fix here is to update the defaults to :: instead of 0.0.0.0. From my research the global IPv6 address covers IPv4 as well, but there may be cases where this is not true. Today, one can override the command template in each chart to fix this, but it's fragile and prone to breakage from future chart updates.

E.g. I added --JsonRpc.EngineHost='::' for Nethermind.