Loops and HTTP control server rework (#308)

- CRUD REST HTTP server
- `/v1` HTTP server prefix
- Retrocompatible with older routes (redirects to v1 or handles the requests directly)
- DNS, Updater and Openvpn refactored to have a REST-like state with new methods to change their states synchronously
- Openvpn, Unbound and Updater status, see #287

internal/models/openvpn.go

@@ -1,6 +1,8 @@
 package models
 
-import "net"
+import (
+	"net"
+)
 
 type OpenVPNConnection struct {
 	IP       net.IP