Extension uninstall hook

[traeok]

Incorporating an uninstall hook in Zowe Explorer and its extenders would provide the following benefits:

• Extenders can use the opportunity to remove any temporary files or settings that they contribute
• We might be able to offer a function in Zowe Explorer API that:
  • evaluates the profile types that an extender contributes and determines which types can be removed
  • performs any other needed cleanup from the Zowe Explorer side to fully remove the extender
• Zowe Explorer can remove any temporary files or settings from VS Code that should not persist after it's uninstalled

Following up on our last stand-up discussion, I'm creating this thread to gather our thoughts on adding this hook and discuss how to make it straightforward for extenders to clean up.

One idea that I had in mind for the uninstall hook is to export a function from Zowe Explorer API, and then have extenders execute it from their uninstall hook:

{
    "scripts": {
        "vscode:uninstall": "node -e \"await import(\"@zowe/zowe-explorer-api\").extenderCleanup()\"" 
    }
}

Taking this a step forward, the extenderCleanup function could support an optional callback parameter to allow extenders to perform extra steps after the API is done with its cleanup steps.