SQLAlchemy: Improve error message when using `database` path parameter

### Problem

When approaching the CrateDB SQLAlchemy dialect with an erroneous connection string including the `database` path parameter, like `crate://localhost/dbname`, it fails using this exception message:
```python
(crate.client.exceptions.ProgrammingError) Connection.__init__() got an unexpected keyword argument 'database'
```

The error message may be improved, specifically because this works well with other databases. However, it can't work with CrateDB, because it does not understand the concept of "databases" at all, but uses "schemas" instead.

### References

- https://github.com/crate/cratedb-examples/pull/174#discussion_r1413249481

No file or test is named. Reproduce the failure with the `crate://localhost/dbname` connection string, then trace SQLAlchemy URL handling in the CrateDB dialect; done means the unsupported `database` parameter produces a clear message explaining that CrateDB uses schemas instead.

Written by the indexing model from the issue text.