Need a way to choose a specific host

Please answer these questions before submitting your issue. Thanks!

### What version of Cassandra are you using?
Scylla 4.1

### What version of Gocql are you using?
latest

### What did you do?
create new session

For monitoring and managing purpose it is useful to read from a node system table.
The system tables are node local so there should be a way to specify the host we want to open the session to.

for example something like:
```
options = &sessionOption{
host: '192.168.1.2',
}
gocql.NewSession(cluster, options)
```

Start at gocql.NewSession and the sessionOption example in the issue, then trace how a session chooses its connected host. Check how node-local system tables are accessed and define done as allowing a caller to target a specific host when opening a session.

Written by the indexing model from the issue text.