Bind to localhost

[tsloughter]

Security WG of EEF flagged the issue of EPMD binding to non-localhost interfaces. I think adding their suggestion of:

-env ERL_EPMD_ADDRESS "127.0.0.1"

-kernel inet_dist_use_interface '{127, 0, 0, 1}'

to vm.args template makes sense.

We'll still just rely on the user setting ERL_DIST_PORT to automatically disable boot of epmd and set a static port for distribution.

Only worry is, now that I think more about it, it is sort of a breaking change more than I was thinking. Now people who expect the defaults to work for deploying a cluster will discover they have to make changes.

I was mainly thinking I wanted a) not to remove -sname/-name from the defaults so the remote console continued to work and b) for local dev of a release to not have any issues.

Not sure if we want a relx 5.0 just for this... Or just do it in a minor release.

[ferd]

If we bump the template, technically nothing in existing releases will change. We can add a comment to the template going along the lines of "remove this argument if you want this to be publicly available, but see the following link for information"

I don't think this is going to be a breaking change if only because everybody's own stuff will keep working with their existing files.