Headerless first column

Add `-FirstColumnName` for tables like:

```PowerShell
$Table = @'
            Total    Copied   Skipped  Mismatch    FAILED    Extras
 Dirs :       332       332       332         0         0         0
Files :      1351      1087       264         0         0         0
Bytes :   1.621 g   1.222 g  408.39 m         0         0         0
'@
```