Use an interface name to find the bind addr for rpc, http and serf components

[diptanu]

This PR allows the operators to specify an interface name which Nomad will use to find an IP address and use it for the http service, serf and rpc.

For example, with the following configuration -

interfaces {
   http = "eth2"
   serf = "eth0"
   rpc = "eth0"
}

Nomad will find the IPs configured for each of the network interfaces and use one of the IPs for binding the network services. IPv4 addresses are given preference over IPv6

[achanda]

Do you think there is any merit in ignoring the loopback IP here? Binding to a loopback IP does not make sense since no one else can access it. This might help if the user mistakenly puts something like lo0

[diptanu]

@achanda This is an operator(sysadmin) setting. We trust the operator to do the right thing.

[dadgar]

Throw some comments on these

[dadgar]

LGTM

[dadgar]

Also documentation for the website

[github-actions]

I'm going to lock this pull request because it has been closed for 120 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.