catalog generation for bigquery

[cmcarthur]

@drewbanin has something partially working for this

[drewbanin]

This is a one-off function from a little bit of experimentation I did recently.

# adapters/bigquery/impl.py

    @classmethod
    def get_catalog(cls, profile, project_cfg, manifest):
        # schemas = cls.get_existing_schemas(profile, project_cfg)
        schemas = list({node.to_dict()['schema'] for node in manifest.nodes.values()})

        columns = []

        for j, schema_name in enumerate(schemas):
            relations = cls.list_relations(profile, project_cfg, schema_name)
            for i, relation in enumerate(relations):
                cols = cls.get_columns_in_table(profile, project_cfg, schema_name, relation.name)
                for col_index, col in enumerate(cols):
                    columns.append({
                        "table_schema": relation.schema,
                        "table_name": relation.name,
                        "table_type": relation.type,
                        "table_comment": None,
                        "column_name": col.name,
                        "column_index": col_index,
                        "column_type": col.data_type,
                        "column_comment": None
                    })


        return dbt.clients.agate_helper.table_from_data(columns)

[drewbanin]

Added in #857, closing