Append a password to an ActiveDirectoryApplication

**Query/Question**
When I update a ActiveDirectoryApplication with passwords, it seems to remove existing ones. How can I append a password to the existing ones?

***Why is this not a Bug or a feature Request?***
This may be a feature request

```
app.update()
.definePasswordCredential("additionalPass")
.withPasswordValue("somePassword")
.attach().apply();
```

Start by tracing the app.update(), definePasswordCredential("additionalPass"), withPasswordValue(), attach(), and apply() entry points shown in the issue. Determine how existing passwords are handled during an update; done means applying an additional password without removing the existing credentials.

Scritto dal modello di indicizzazione a partire dal testo della issue.