feat(jans-orm): support `AttributeName` annotation on byte arrays

A bean with a field like

```
@AttributeName(name = "mybinattribute") private byte[] field;
...
getter + setter here
```

Generates this error when trying to persist the bean:

```
'io.jans.orm.exception.MappingException: Entry property 'continuation' should has getter with String, String[], Boolean, Integer, Long,
Date, List, AttributeEnum or AttributeEnum[] return type or has annotation JsonObject'
```

ORM seems to expect the annotation over a (Java) `String` field already containing a base64 representation.

It would be better if it works directly on the byte array field thus saving the base64 encoding/decoding.