feat: caddy deploy command and stub implementation

internal/cli/client/caddy.go

@@ -0,0 +1,10 @@
+package client
+
+import (
+	"context"
+	"errors"
+)
+
+func (cli *Client) DeployCaddy(ctx context.Context, image string) error {
+	return errors.New("not implemented")
+}