Support multiple values for alternateName

In the general case, `alternateName` can have multiple values. Review the code and check if this possibility is accounted for. Example:

```json
{
    "@id": "94e723dc305f28b58ba1aba04e14aade037baa95/da39a3ee5e6b4b0d3255bfef95601890afd80709",
    "@type": "File",
    "alternateName": ["logs/my_step.out", "logs/my_step.err"],
    "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709"
},
```
