Missing documentation for xpack options

[elasticmachine]

Original comment by @jakelandis:

For the following x-pack options, I could not find documentation:

xpack.monitoring.elasticsearch.ssl.verification_mode
xpack.monitoring.collection.pipeline.details.enabled

and

xpack.management.elasticsearch.sniffing

• xpack.monitoring.elasticsearch.ssl.verification_mode - certificate or none
• xpack.monitoring.collection.pipeline.details.enabled - not 100% exactly what this does... i think this enables the data for the graph view of metrics
• xpack.management.elasticsearch.sniffing - same as the monitoring variant.