Outdated third party logging documentation

[shazron]

Issue in /src/pages/guides/using/logging_monitoring.md
I/O Runtime doesn’t offer a configuration to send activations and logs to an external system, something like Splunk, Datadog or New Relic. This is something we are considering to offer in the future.

We do support Splunk and Azure Logs: https://developer.adobe.com/app-builder/docs/guides/application_logging/#forwarding-application-logs
New Relic support is a feature request: adobe/aio-cli#348