fix(hive): reject metastore URIs without a host

[fallintoplace]

What changed

• Require a hostname before creating a Hive metastore client.
• Reject authority-less URIs and URIs with an empty host.
• Keep the default port at 9083 when the URI has no port.

Why

url.Parse accepts values such as thrift://:9083 and localhost:9083 without providing a host for the metastore connection. These values now fail before the client is created.

Tests

• go test ./catalog/hive -count=1
• go test ./... -count=1