Allow WHERE push-down

We're transferring chunks of data via the ODBC-Bridge to ClickHouse from SAP HANA using the odbc() function.

Unfortunately, the WHERE condition of the query is not yet pushed down to HANA (similar to e.g. to the mysql function), and all data from the HANA table is transferred to ClickHouse, which does the WHERE. This makes the ODBC-bridge unusable in our case (as the remote table is huge, and must be filtered).

We're doing something like this:

**SELECT * FROM odbc("", "", "") WHERE date='20250101' AND something='123';**

So either the query condition should be pushed down, or alternatively, a SELECT should be allowed in the function call instead of a table name, something like:

**SELECT * FROM odbc("", "", "SELECT * FROM WHERE date='20250101' AND something='123'");**