Add CloudDocs documentation for metric descriptions

[megamattzilla]

Is your feature request related to a problem? Please describe.

Understanding the resulting TS metrics and making them useful can be difficult. It would be helpful to have documentation explaining the metrics so that customers make better use of them.

Describe the solution you'd like

A page on cloud docs that explain the metrics output and any recommendations on analysis like aggregate or average/sum.
Example data from Azure LB metrics: https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-standard-diagnostics

Additional context

Example: a customer is reviewing metric output from Prometheus pull consumer and it can be difficult to identify what these metrics are for:

f5_system_configSyncSucceeded
f5_counters_bitsIn,
f5_numberReqs
f5_2xxResp,f5_3xxResp,f5_4xxResp,f5_5xxResp
f5_counters_bitsOut

[tizianorosato-gr]

Hi, some metrics are not so intuitive.
Prometheus metrics documentation will be greatly useful.