Support H2 in vertx-sql-client

### Describe the feature

Quarkus reactive tests are currently based on Postgresql because there's no H2 vertx-sql-client.

On the other hand, Hibernate blocking tests are using H2, and therefore they might be faster to run.

Even thought it might not be interesting in a production scenario, a H2 vertx-sql-client might be useful for testing.

I can work on this in my spare time

### Contribution

_No response_