CDK-215: Add warning for local metastore.

This adds a WARN message when a user connects to a local MetaStore
because it is not recommended in practice. Hive 0.10 and later will
connect to a local metastore by default if hive.metastore.uris is not
set; hive.metastore.local has been removed.
CDK-215: Fix hcatalog's Loader debug logging.

URI options are now logged at DEBUG and include whether the options were
passed to a managed or external builder.