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

- create an example to use coredns module for adding dns records
- fix module errors

examples/osal/coredns/example.vsh

@@ -0,0 +1,20 @@
+#!/usr/bin/env -S v -n -w -gc none  -cc tcc -d use_openssl -enable-globals run
+
+import freeflowuniverse.herolib.installers.infra.coredns as coredns_installer
+import freeflowuniverse.herolib.osal.coredns
+import freeflowuniverse.herolib.core.playbook
+
+// coredns_installer.delete()!
+mut installer := coredns_installer.get()!
+// coredns_installer.fix()!
+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"
+'
+
+mut plbook := playbook.new(text: script)!
+coredns.play_dns(mut plbook)!

lib/installers/infra/coredns/coredns_actions.v

@@ -51,7 +51,7 @@ fn stop_post() ! {
 
 // checks if a certain version or above is installed
 fn installed() !bool {
-	res := os.execute('${osal.profile_path_source_and()!} coredns version')
+	res := os.execute('/bin/bash -c "${osal.profile_path_source_and()!} coredns --version"')
 	if res.exit_code != 0 {
 		return false
 	}

lib/osal/coredns/model.v

@@ -1,3 +1,7 @@
+module coredns
+
+import freeflowuniverse.herolib.core.redisclient
+
 // Input parameter structs for each record type
 @[params]
 struct SRVRecord {