This rewrites the HTTP Exporter to use the REST client underneath. Functionality is improved in resource blocking (templates and pipelines existing) and the majority of the code fundamentall simplified by removing direct HTTP calls.
This is blocked by the SSLService pull request. After that is merged, the I will update this PR to reflect those changes and it could possibly allow us to remove the security privileges required for monitoring.
Original commit: elastic/x-pack-elasticsearch@1ad25f17f8