Show sources in config string

and remove directory which is only meant to be used by yip configs (not
user configs read by the kairos-agent).

This needs to be explained in the release notes.

Needs this: https://github.com/kairos-io/kairos-sdk/pull/501

Part of: https://github.com/kairos-io/kairos/issues/2737

Signed-off-by: Dimitris Karakasilis <dimitris@karakasilis.me>

main.go

@@ -334,7 +334,7 @@ E.g. kairos-agent install-bundle container:quay.io/kairos/kairos...
 
 			configStr, err := config.String()
 			if err != nil {
-				return err
+				return fmt.Errorf("getting config string: %w", err)
 			}
 			fmt.Printf("%s", configStr)
 			return nil