Add descriptions for API key API

[abdonpijpelink]

Adds descriptions for these API key APIs:

• Create API key
• Grant API key
• Update API key
• Get API key information
• Invalidate API key
• Query API key information
• Clear API key cache

Source for the descriptions: https://www.elastic.co/guide/en/elasticsearch/reference/master/security-api.html#security-api-keys

I also had to add the read_security cluster privilege. It was missing from utils.ts, but it is mentioned in several docs. I don't know if that was the right thing to do?

[lcawl]

LGTM

[github-actions]

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

API	Status	Request	Response
security.activate_user_profile	⚪	Missing test	Missing test
security.authenticate	🟢	15/15	15/15
security.bulk_update_api_keys	🟠	Missing type	Missing type
security.change_password	🟢	6/6	6/6
security.clear_api_key_cache	🟢	9/9	9/9
security.clear_cached_privileges	🟢	3/3	3/3
security.clear_cached_realms	🟢	1/1	1/1
security.clear_cached_roles	🟢	2/2	2/2
security.clear_cached_service_tokens	🟢	4/4	4/4
security.create_api_key	🟢	25/25	16/16
security.create_cross_cluster_api_key	🟠	Missing type	Missing type
security.create_service_token	🟢	2/2	2/2
security.delete_privileges	🟢	6/6	6/6
security.delete_role_mapping	🟢	9/9	9/9
security.delete_role	🟢	8/8	8/8
security.delete_service_token	⚪	Missing test	Missing test
security.delete_user	🟢	9/9	9/9
security.disable_user_profile	⚪	Missing test	Missing test
security.disable_user	🟢	3/3	3/3
security.enable_user_profile	⚪	Missing test	Missing test
security.enable_user	🟢	4/4	4/4
security.enroll_kibana	⚪	Missing test	Missing test
security.enroll_node	⚪	Missing test	Missing test
security.get_api_key	🟢	14/14	14/14
security.get_builtin_privileges	🟢	2/2	2/2
security.get_privileges	🟢	12/12	12/12
security.get_role_mapping	🟢	18/18	18/18
security.get_role	🟢	20/20	20/20
security.get_service_accounts	⚪	Missing test	Missing test
security.get_service_credentials	🟢	1/1	1/1
security.get_token	🟢	21/21	20/20
security.get_user_privileges	🟢	7/7	7/7
security.get_user_profile	⚪	Missing test	Missing test
security.get_user	🟢	24/24	24/24
security.grant_api_key	⚪	Missing test	Missing test
security.has_privileges_user_profile	⚪	Missing test	Missing test
security.has_privileges	🟢	9/9	9/9
security.invalidate_api_key	🟢	10/10	10/10
security.invalidate_token	🟢	11/11	11/11
security.oidc_authenticate	🟠	Missing type	Missing type
security.oidc_logout	🟠	Missing type	Missing type
security.oidc_prepare_authentication	🟠	Missing type	Missing type
security.put_privileges	🟢	10/10	10/10
security.put_role_mapping	🟢	11/11	11/11
security.put_role	🟢	26/26	25/25
security.put_user	🟢	39/39	38/38
security.query_api_keys	🟢	7/7	7/7
security.saml_authenticate	⚪	Missing test	Missing test
security.saml_complete_logout	⚪	Missing test	Missing test
security.saml_invalidate	⚪	Missing test	Missing test
security.saml_logout	⚪	Missing test	Missing test
security.saml_prepare_authentication	⚪	Missing test	Missing test
security.saml_service_provider_metadata	⚪	Missing test	Missing test
security.suggest_user_profiles	⚪	Missing test	Missing test
security.update_api_key	⚪	Missing test	Missing test
security.update_cross_cluster_api_key	🟠	Missing type	Missing type
security.update_user_profile_data	⚪	Missing test	Missing test

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