Feature Request: support temp property graphs

[Dtenwolde]

Why do you want this feature?
Similar to DuckDB’s temporary tables, we van add support for temporary property graphs. These would only exist for the current connection and be dropped whenever the connection is closed. This would be easy to support. We don’t write the temporary property graphs to the __duckpgq_internal table and only add it to the in-memory map that holds information on the currently registered property graphs. Would require changes to the parser and transformer to detect whenever a property graph is temporary