[ELE-42] Add support to _PARTITIONTIME as timestamp column in Bigquery

[Maayan-s]

In Bigquery partitioned tables have a pseudo-column named _PARTITIONTIME. https://cloud.google.com/bigquery/docs/querying-partitioned-tables

Before running the test query, Elementary checks the information schema to see if the column provided as the timestamp column exists or not. As I assume _PATITIONTIME is not there, it ignores it (we don't want to query a missing column and fail).

Requested on Slack by Krzystof D.

_ELE-42

[github-actions[bot]]

This issue is stale because it has been open for too long with no activity. If you would like the issue to remain open, please remove the stale label or leave a comment.