Update supported configurations topic for OSSM 2.2

When we first wrote the supported configurations topic (ossm-supported-configurations.adoc), there was only one release of OCP 4.x.  So the current content reads:

https://docs.openshift.com/container-platform/4.10/service_mesh/v2x/preparing-ossm-installation.html#ossm-supported-configurations_preparing-ossm-installation

 
The following configurations are supported for the current release of Red Hat OpenShift Service Mesh:

• Red Hat OpenShift Container Platform version 4.x.

We should change "4.x" to read "4.9" for the OSSM 2.2 release.

Also from GitHub issue #43023

Which section(s) is the issue in?

Service Mesh 2.x -> Preparing to Install Service Mesh -> Supported Mixer Adapters
This section indicates that the Mixer adapter for 3scale is supported. However, the 2.1.1 release notes say:
"With Mixer now officially removed, OpenShift Service Mesh 2.1 does not support the 3scale mixer adapter."

https://docs.openshift.com/container-platform/4.9/service_mesh/v2x/preparing-ossm-installation.html#ossm-supported-configurations-adapters_preparing-ossm-installation

What needs fixing?

Probably remove the section on supported mixer adapters. Maybe add something about the WebAssembly module.

One last thing - Check YAML files (especially SMCP)  for versions, change

spec.version: v2.0  to v2.1