[Java] Ability to use a path based host when using the JDBC driver

### Describe the enhancement requested

From an infrastructure perspective, it would be easier for us to do path based routing for our Flight server instead of sub-domain based routing. For example, `https://mydomain.com/grpc/flight`. A model like this would allow us to create routing rules for all grpc services we expose within our company using shared architecture.

Looking around at `getUrlsArgs` , there seems to be no use for the `path` part of the JDBC URI, so I see a few ways this could be implemented:

```
jdbc:arrow-flight-sql://mydomain.com/grpc/flight:443
jdbc:arrow-flight-sql://https://mydomain.com/grpc/flight:443
jdbc:arrow-flight-sql://mydomain.com:443/grpc/flight
jdbc:arrow-flight-sql://https://mydomain.com:443/grpc/flight
```

This seems to be fairly uncommon, but there's at least one other driver that does this. For example, the Simba BigQuery connection looks like this:

```
jdbc:bigquery://https://www.googleapis.com/bigquery/v2:443;ProjectId=;OAuthType=0;OAuthServiceAcctEmail=;OAuthPvtKeyPath=;
```

I'm not sure if this is already supported by the `Avatica` driver, so it may also need some changes there.

### Component(s)

Java

Beginne damit, die im Issue erwähnte getUrlsArgs-Logik zu lesen, und verfolge, wie die Java JDBC URI geparst wird. Prüfe, ob der Avatica-Treiber einen host auf Pfadbasis unterstützt, definiere dann die akzeptierte URI-Form und verifiziere das daraus resultierende Routing-Verhalten mit Tests; das Issue nennt keine spezifischen Dateien oder Tests.

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