[#1714] lens: Separate commands

Separate `inspect` and `list` on `write-cache` and `blobovnicza`
subcommands.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

cmd/neofs-lens/internal/errors.go

@@ -0,0 +1,31 @@
+package common
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+// Errf returns formatted error in errFmt format if err is not nil.
+func Errf(errFmt string, err error) error {
+	if err == nil {
+		return nil
+	}
+
+	return fmt.Errorf(errFmt, err)
+}
+
+// ExitOnErr calls exitOnErrCode with code 1.
+func ExitOnErr(cmd *cobra.Command, err error) {
+	exitOnErrCode(cmd, err, 1)
+}
+
+// exitOnErrCode prints error via cmd and calls os.Exit with passed exit code.
+// Does nothing if err is nil.
+func exitOnErrCode(cmd *cobra.Command, err error, code int) {
+	if err != nil {
+		cmd.PrintErrln(err)
+		os.Exit(code)
+	}
+}