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/settings/openvpn.go

@@ -12,9 +12,9 @@ import (
 // OpenVPN contains settings to configure the OpenVPN client.
 type OpenVPN struct {
 	User      string                  `json:"user"`
-	Password  string                  `json:"-"`
+	Password  string                  `json:"password"`
 	Verbosity int                     `json:"verbosity"`
-	Root      bool                    `json:"runAsRoot"`
+	Root      bool                    `json:"run_as_root"`
 	Cipher    string                  `json:"cipher"`
 	Auth      string                  `json:"auth"`
 	Provider  models.ProviderSettings `json:"provider"`