Raise informative error when importing non-installed module
With this PR, we raise a specific informative error when a dataset script tries to import a module/library that is not installed.

Note that once we propagate error messages from the children jobs, we only need this message in the root job "/config-names".

Fix #1083.
Raise informative error when importing non-installed module: With this PR, we raise a specific informative error when a dataset script tries to import a module/library that is not installed.

Note that once we propagate error messages from the children jobs, we only need this message in the root job "/config-names".

Fix #1083.