Raise exception if filtering on tag not present in Dataset

Instead of returning an empty dataset, raise an exception when filtering on the tag that does not exist.

e.g. one will get:

$ apd-list-pfns SL rds_hadronic --tag event_type --value  13863401 --polarity magdown
ValueError: Tag event_type unknown. Did you mean eventtype ?
Available tags: config, polarity, eventtype, datatype, version, name, state

To be merged after !24 (merged) as it includes it too to have the changes on the gitlab-ci.

Closes #10 (closed)