AutoScenarioDbTable.create_table_metadata() also extract the columns_metadata

[victorterpstra]

For the AutoScenarioDbTable, we get the sqlalchemy.Table from reflection.
We also need the columns_metadata to be able to cell edits.
In particular, the method ScenarioDbTable.get_sa_column is searching for a sqlalchemy.Column and can't find it because it has not been reflected.

Work-around:
Do not use AutoScenarioDbTable