WIP(osal.coredns): add example for coredns usage

- added openssl and iproute2 installation to install_v.sh since they're
  needed in coredns installation and usage.
- fixed bug in coredns build process.
- fixed bug in getting own public ip.
- fixed bugs in json encoding dns records before pushing to redis

examples/osal/coredns/example.vsh

@@ -1,4 +1,4 @@
-#!/usr/bin/env -S v -n -w -gc none  -cc tcc -d use_openssl -enable-globals run
+#!/usr/bin/env -S v -n -w -cg -d use_openssl -enable-globals run
 
 import freeflowuniverse.herolib.installers.infra.coredns as coredns_installer
 import freeflowuniverse.herolib.osal.coredns
@@ -11,10 +11,36 @@ installer.start()!
 
 // TODO: create heroscript and run it to add dns records
 mut script := '
-dns.a_record
-	name: "a_rec1"
-	ip: "1.1.1.1"
-'
+!!dns.a_record
+    name: "host1"
+    ip: "1.1.1.1"
+
+!!dns.aaaa_record
+    name: "host2"
+    ip: "2001:db8::1"
+    ttl: 300
+
+!!dns.mx_record
+    host: "mail.heroexample.com"
+    preference: 10
+    ttl: 300
+
+!!dns.txt_record
+    text: "v=spf1 mx ~all"
+    ttl: 300
+
+!!dns.srv_record
+    target: "sip.heroexample.com"
+    port: 5060
+    priority: 10
+    weight: 100
+    ttl: 300
+
+!!dns.ns_record
+    host: "ns1.heroexample.com"
+    ttl: 300
+    '
 
 mut plbook := playbook.new(text: script)!
-coredns.play_dns(mut plbook)!
+rec := coredns.play_dns(mut plbook)!
+rec.set('heroexample.com')!