[#51186427] user can open a work flow based on a Hdfs Data Source

- add a javascript fixture for an Alpine work flow with an Hdfs Data Source
- Iframe url sends hdfs_data_source_id instead of database_id
- Workfile show page shows the Hdfs Data Source as the execution location
- Defined an "attempt_connection" method for Gpdb Data Sources to verify credentials before opening alpine
- Defined "attempt_connection" on other Data Sources, such as Hdfs, as a no-op so that Hdfs & Gpdb have a common duck type