feat: add ability to set the ipv4/ipv6 bind address for an app

This allows users to handle mulitple interfaces separately or even ensure applications remain accessible only on a local network.

Closes #3805

tests/unit/40_nginx-vhosts_2.bats

@@ -107,6 +107,55 @@ assert_error_log() {
   assert_failure
 }
 
+@test "(nginx-vhosts) nginx:set bind-address" {
+  run deploy_app
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:set $TEST_APP bind-address-ipv4 127.0.0.1"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:set $TEST_APP bind-address-ipv6 ::1"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:build-config $TEST_APP"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:show-conf $TEST_APP"
+  echo "output: $output"
+  echo "status: $status"
+  assert_output_contains "[::1]:80;"
+  assert_output_contains "127.0.0.1:80;"
+
+  run /bin/bash -c "dokku nginx:set $TEST_APP bind-address-ipv4"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:set $TEST_APP bind-address-ipv6"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:build-config $TEST_APP"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku nginx:show-conf $TEST_APP"
+  echo "output: $output"
+  echo "status: $status"
+  assert_output_contains "[::1]:80;" 0
+  assert_output_contains "127.0.0.1:80;" 0
+}
+
 @test "(nginx-vhosts) nginx:validate" {
   deploy_app
   run /bin/bash -c "dokku nginx:validate"