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_test.go

@@ -20,7 +20,7 @@ func Test_OpenVPN_JSON(t *testing.T) {
 	data, err := json.Marshal(in)
 	require.NoError(t, err)
 	//nolint:lll
-	assert.Equal(t, `{"user":"","verbosity":0,"runAsRoot":true,"cipher":"","auth":"","provider":{"name":"name","serverSelection":{"networkProtocol":"","regions":null,"group":"","countries":null,"cities":null,"hostnames":null,"isps":null,"owned":false,"customPort":0,"numbers":null,"encryptionPreset":""},"extraConfig":{"encryptionPreset":"","openvpnIPv6":false},"portForwarding":{"enabled":false,"filepath":""}}}`, string(data))
+	assert.Equal(t, `{"user":"","password":"","verbosity":0,"run_as_root":true,"cipher":"","auth":"","provider":{"name":"name","server_selection":{"network_protocol":"","regions":null,"group":"","countries":null,"cities":null,"hostnames":null,"isps":null,"owned":false,"custom_port":0,"numbers":null,"encryption_preset":""},"extra_config":{"encryption_preset":"","openvpn_ipv6":false},"port_forwarding":{"enabled":false,"filepath":""}}}`, string(data))
 	var out OpenVPN
 	err = json.Unmarshal(data, &out)
 	require.NoError(t, err)