NGINX: configurable listen addresses

[bimbar]

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Is your feature request related to a problem? Please describe.

Referencing issue #973

We have clients that have multiple public IPs so that they can have each public IP serve a different purpose. If I just configure a nginx at port 443, I destroy that advantage, and make every public IP the same, so I might just have a single one.

Describe the solution you'd like

So, I'm willing to do the work, which should not be much, the plan being:

changing "listen port" and "ssl listen port" to "listen address" and "ssl listen address" functionally identical to the address field of haproxy
on packet installation migrating existing listen ports to listen addresses, here with the example of port 80:
"80" -> "80", "[::]:80"

So, in order not to waste everyones time, if I create such a pull request and it passes code checks, would it be accepted, or is that functionality just not wanted, as it seems to be according to issue #973?

Describe alternatives you've considered

Using HAProxy, since nginx, while preferred, is useless to me this way.

Additional context
Add any other context or screenshots about the feature request here.

[bimbar]

it ate my formatting, so:

proposed solution:

• changing "listen port" and "ssl listen port" to "listen address" and "ssl listen address" functionally identical to the address field of haproxy
• on packet installation migrating existing listen ports to listen addresses, here with the example of port 80:
  "80" -> "80", "[::]:80"

[bimbar]

Might even be possible to do #1218 at the same time.

[bimbar]

See Pull Request #2578 .