Better error catching for Nautilus Driver

[seg1129]

When retrieving sample data from nautilus, there should be better error catching in the following scenarios:

1. If SDG exists but no aliquots are aligned to the SDG - this should be a notification not a warning
2. indicate when a user credentials are wrong/ user does not have access to protocol in nautilus (401 error)
3. Indicate if SDG does not exist in nautilus (404 error)

[seg1129]

These Errors are now coming through nautilus-rest. Need to modify Nautilus driver to make user aware of these errors.