Add some notes and support regulations to APIs section on the Docs

Proposed title of this feature request

Add some notes and support regulations to APIs section on the Docs.

Accessing third-party monitoring UIs and APIs:
https://docs.openshift.com/container-platform/4.10/monitoring/accessing-third-party-monitoring-uis-and-apis.html#accessing-third-party-monitoring-web-service-apis

What is the nature and description of the request?

Add some notes and support regulations to "Accessing third-party monitoring web service APIs" section.
According to the documentation, we can directly access the 3rd party web service API from the command line.
But the notes about it are minimal.

So a customer has questions such as:

For example:
- Will Red Hat ensure that users can call Prometheus API with the same way even with the future versions of OpenShift?
- Will Red Hat support team handle questions like below and investigate?
  + How to call Prometheus API
  + Users called Prometheus API but they got wrong values
  + How many requests/sec can we send ?

We can find a note about the number of requests in the "Querying metrics by using the federation endpoint for Prometheus" section.

It would be helpful if there was a note like this in the "Accessing third-party monitoring web service APIs" section.And also, please consider adding a link to API tier as well.

Understanding API tiers: https://docs.openshift.com/container-platform/4.10/rest_api/understanding-api-support-tiers.html

Why does the customer need this? (List the business requirements)

The customer wants us to specify it in the official documentation.
The problem of https://docs.openshift.com/container-platform/4.10/monitoring/accessing-third-party-monitoring-uis-and-apis.html#accessing-third-party-monitoring-web-service-apis is that:

• Red Hat mentions WARNING for "/federate" endpoint.
• But there is no WARNING for other "/api" endpoints.

So customers would think that they can ignore WARNING mentioned for "/federate" when accessing "/api" endpoints.
But we believe that we should give the same WARNING even for "/api" endpoints.

So,

It would be helpful if there was a note like this in the "Accessing third-party monitoring web service APIs" section.

List any affected packages or components.

• Docs