feat: Add support for Hetzner Storage Box integration

- Introduced new source and destination forms for Hetzner Storage Box, allowing users to configure their storage settings.
- Updated configuration generation logic to handle Hetzner, including necessary parameters such as host, port, username, and authentication type.
- Enhanced user interface with clear instructions and security notes for Hetzner, improving user experience and security awareness.
- Updated existing logic to accommodate Hetzner in rclone configuration generation for both source and destination types.

internal/db/transfer_config_store.go

@@ -91,7 +91,7 @@ func (db *DB) GenerateRcloneConfig(config *TransferConfig) error {
 	sourceName := fmt.Sprintf("source_%d", config.ID)
 	// Generate rclone config using rclone CLI for source
 	switch config.SourceType {
-	case "sftp":
+	case "sftp", "hetzner":
 		args := []string{
 			"config", "create", sourceName, "sftp",
 			"host", config.SourceHost,
@@ -245,7 +245,7 @@ func (db *DB) GenerateRcloneConfig(config *TransferConfig) error {
 	destName := fmt.Sprintf("dest_%d", config.ID)
 	// Generate rclone config using rclone CLI for destination
 	switch config.DestinationType {
-	case "sftp":
+	case "sftp", "hetzner":
 		args := []string{
 			"config", "create", destName, "sftp",
 			"host", config.DestHost,