[Kiali] Document how to access Workload Logs (app and Proxy Logs) from Kiali

Under the new "Metrics, Logs and Traces" section, add a small section that describes how to access logs from Kiali. This is loosely documented in the upstream Kiali docs here: https://kiali.io/documentation/latest/features/#_detail_logs.  

https://kiali.io/docs/features/details/#logs

When the module is finished, rename the assembly to Metrics, traces, and logs. It is currently Metrics and traces.

https://docs.openshift.com/container-platform/4.7/service_mesh/v2x/ossm-observability.html