config: make config create/update encrypt passwords where necessary

Before this change when using "rclone config create" it wasn't
possible to add passwords in one go, it was necessary to call "rclone
config password" to add the passwords afterwards as "rclone config
create" didn't obscure passwords.

After this change "rclone config create" and "rclone config update"
will obscure passwords as necessary as will the corresponding API
calls config/create and config/update.

This makes "rclone config password" and its API config/password
obsolete, however they will be left for backwards compatibility.

fs/config/config.go

@@ -935,9 +935,38 @@ func suppressConfirm() func() {
 // keyValues should be key, value pairs.
 func UpdateRemote(name string, keyValues rc.Params) error {
 	defer suppressConfirm()()
+
+	// Work out which options need to be obscured
+	needsObscure := map[string]struct{}{}
+	if fsType := FileGet(name, "type"); fsType != "" {
+		if ri, err := fs.Find(fsType); err != nil {
+			fs.Debugf(nil, "Couldn't find fs for type %q", fsType)
+		} else {
+			for _, opt := range ri.Options {
+				if opt.IsPassword {
+					needsObscure[opt.Name] = struct{}{}
+				}
+			}
+		}
+	} else {
+		fs.Debugf(nil, "UpdateRemote: Couldn't find fs type")
+	}
+
 	// Set the config
 	for k, v := range keyValues {
-		getConfigData().SetValue(name, k, fmt.Sprint(v))
+		vStr := fmt.Sprint(v)
+		// Obscure parameter if necessary
+		if _, ok := needsObscure[k]; ok {
+			_, err := obscure.Reveal(vStr)
+			if err != nil {
+				// If error => not already obscured, so obscure it
+				vStr, err = obscure.Obscure(vStr)
+				if err != nil {
+					return errors.Wrap(err, "UpdateRemote: obscure failed")
+				}
+			}
+		}
+		getConfigData().SetValue(name, k, vStr)
 	}
 	RemoteConfig(name)
 	SaveConfig()