Add query capability to Python plugin API

[pauldix]

As part of #25654, #25618, and #25537, plugin authors will need the ability to query the database and get results back for use in their scripts. If should be part of the API pointer that gets handed to the various plugin entry point functions.

For now we can create a function that return rows like the kind yielded to the WAL plugins (see: https://github.com/influxdata/influxdb/blob/main/influxdb3_py_api/src/system_py.rs#L412-L459). Later we'll want to give users an option to return Arrow along with a dataframe API, but this should be enough to make something useful.

The function will by default query the database that a plugin is tied to (via its trigger) or take an optional parameter to specify a different database. They should take an optional PyDict with parameterized query arguments. So we have:

def query_rows(self, query: str, parameters: Optional[Dict[str, Any]] = None, database: Optional[str]) -> Row