[Bug] JPMS support

### Search before asking

- [ ] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Version

3.0.0

### Minimal reproduce step

Try to use `pulsar-client-api` with JPMS.

### What did you expect to see?

A `module-info` file and support for JPMS in the client.

### What did you see instead?

```java
[WARN] **********************************************************************************************************************************************************************************************************
[WARN] * Required filename-based automodules detected: [pulsar-client-api-3.0.0.jar]. Please don't publish this project to a public artifact repository! *
[WARN] **********************************************************************************************************************************************************************************************************
```

### Anything else?

See https://github.com/apache/pulsar/issues/7971 - the issue was closed as stale but still takes effect, 3 years later.

I am willing to submit a PR (did check the box) but I'm not sure what is desired, and where to make the changes, so it's ideal if somebody with more experience in this project makes the changes. The main issue is if the client needs to retain Java 8 support - then the `module-info` needs to be built separately with either Java 9, or Java 11 (as it's the following LTS), so that JPMS can be supported alongside regular Java 8 classpath.

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!