Don't expose the username / password when importing datasource using import_datasource sqlalchemy_uri

[noamliber-reco]

I would expect this to be hidden or at least censored with ****:
currently it is displayed in cleartext.
I don't want the end-user of Superset to know the password, just to use it thru Superset.

those Database connections have been imported with the import_datasources.yaml as described in the k8s installation guide