Clearly document what SDK versions work with what OpenShift versions

As a dynamic plugin developer, I want to know what SDK and webpack plugin versions are supported for what OpenShift versions so I can choose the correct dependency.

We need to make sure it's clear what SDK and webpack plugin versions work with what OpenShift versions. Right now this is not documented. After discussing in the plugin sync call, we proposed the following AC.

Acceptance Criteria:

• Use semver for SDK package versions. The package versions will not follow OpenShift versions (so we can correctly bump major and minor versions for features and breaking changes)
• Add a tab that tracks the latest package for a particular OpenShift version like `latest-4.10`
• Create a table of version compatibility
• Publishing the version tables for both https://www.npmjs.com/package/@openshift-console/dynamic-plugin-sdk and https://www.npmjs.com/package/@openshift-console/dynamic-plugin-sdk-webpack packages.

Out of scope

We also discussed doing build-time validation of the package version against the `@console/pluginAPI` version declared in the `consolePlugins` stanza. This is out of scope for this story and can be tracked by a separate story.

cc jhadvig@redhat.com vszocs@redhat.com