Add information for extension TS rework

[cnotv]

Description

Create documentation as an outcome of the TS rework due to Vue3 migration.

For example

• "Implementations of IClusterProvisioner can now get Component as import type { Component } from 'vue';"
• "Import paths should be complete, starting with @pkg"
• etc

[cnotv]

Closing as issues have been fixed and can be used as examples.