Add schema parameter to RedshiftSource to distinguish between database schemas #1767

Is your feature request related to a problem? Please describe.
No possible way to specify schema via table parameter.
When you add schema parameter to table name e.g schema_sample.feature_table it throws exception when applying with message:

    raise DataSourceNotFoundException(self.table)
feast.errors.DataSourceNotFoundException: Unable to find table at 'schema_sample.feature_table'. Please check that table exists.

Describe the solution you'd like
Add optional schema parameter to uniquely identify which schema to use to reference source table.

Describe alternatives you've considered
query parameter works just fine