Provide Java Module name

Truth doesn't provide an `AUTOMATIC-MODULE-NAME`, like `com.google.truth`, via its manifest. [PresentModule.java](https://github.com/sormuras/modules/blob/master/src/PresentModule.java) yields:

```
java PresentModule.java com.google.truth:truth:1.0
path = truth-1.0.jar
name = truth
mode = automatic
automatic name source = FILENAME
api = 1 package(s)
```

At least, provide a more stable module name via Truth's manifest.

Better, provide a compiled module descriptor.

See also https://github.com/google/error-prone/issues/1116 and linked friends.