Ensure all objects with config_yaml have get-by-ID/get-by-name

[cph-datamasque]

The list endpoints for rulesets, ruleset libraries, discovery configs do not include config_yaml in the response (for performance).

But, the client doesn't expose a way to GET an individual object detail, other than doing a raw API request.

Add get_blah_by_name / get_blah_by_id methods for all objects that need it, i.e. where the list endpoint hides certain fields but the detail endpoint exposes them.