[C++] Right-justify array values in PrettyPrint

Currently we the output of `PrettyPrint` for an array looks as follows:

```Java

[
1,
NA
]
```

We should right-justify it for better readability:

```Java

[
1,
NA
]
```

**Reporter**: [Uwe Korn](https://issues.apache.org/jira/browse/ARROW-2885) / @xhochy
#### Related issues:
- [PrettyPrint Improvements](https://github.com/apache/arrow/issues/33527) (is a child of)

_{**Note**: *This issue was originally created as [ARROW-2885](https://issues.apache.org/jira/browse/ARROW-2885). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}