Reversions suggested on PR
Reversions suggested on PR

- Revert `DataSourceNotFound` base class to `Exception`.
  `OSError` should ideally preserve errno / strerror attributes, and
  by now `DataSourceNotFound` can originate from too many other
  exceptions that are not necessarily OSErrors.
- Revert premature chunk store inference from RDB URL. It was done to
  save some time but the small gain is not worth it. The RDB URL may
  not be a reliable indicator of the default chunk store URL after all
  (consider continuum imaging data in on-site Ceph store).
- Catch the generic `ChunkStoreError` instead of specifics.

ska-sa/katdal