feat(unix): add support for bolt+unix (#1700)

The new `bolt+unix` scheme allows connecting to Neo4j server over a Unix socket.

Example:
```java
try (var driver = GraphDatabase.driver("bolt+unix:///var/run/neo4j.sock")) {
    // use the driver
    var result = driver.executableQuery("SHOW DATABASES")
            .withConfig(QueryConfig.builder().withDatabase("system").build())
            .execute();
    result.records().forEach(System.out::println);
}
```