Add query rule API examples

[lcawl]

Relates to #2482

This PR copies examples from https://www.elastic.co/guide/en/elasticsearch/reference/master/query-rules-apis.html

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
query_rules.delete_rule	🟢	6/6	6/6
query_rules.delete_ruleset	🟢	7/7	7/7
query_rules.get_rule	🟢	5/5	5/5
query_rules.get_ruleset	🟢	8/8	8/8
query_rules.list_rulesets	🟢	8/8	8/8
query_rules.put_rule	🟢	7/7	7/7
query_rules.put_ruleset	🟢	16/16	16/16
query_rules.test	🟢	9/9	9/9

You can validate these APIs yourself by using the make validate target.