Display a friendly message on system uninstall with podman endpoint and controller not installed

[fgiorgetti]

Is your feature request related to a problem? Please describe.
If the system-controller and/or the podman socket endpoint are not running, and user runs the
skupper system uninstall command, an error message is being displayed, see:

failed to uninstall : failed to create container client: container engine is not available on the provided endpoint: "unix:///run/user/1000/podman/podman.sock" (unable to verify version) - Get "http://unix/version": dial unix /run/user/1000/podman/podman.sock: connect: connection refused

Describe the solution you'd like
On such error, skupper could educate user to run system install first, as it is unable to communicate with the container engine.

[lynnemorrison]

@fgiorgetti we are currently printing out the error message received back from cmd.systemUninstall function.

do you just want the existing error message and then a second message indicating user needs to run system install?
or just a shortened message

failed to uninstall : failed to communicate with container engine, need to run "skupper system install" to start system-controller and/or the podman socket endpoint

or

failed to uninstall : failed to create container client: container engine is not available on the provided endpoint: "unix:///run/user/1000/podman/podman.sock" (unable to verify version) - Get "http://unix/version": dial unix /run/user/1000/podman/podman.sock: connect: connection refused
First issue "skupper system install" to install system-controller and/or the podman socket endpoint

[fgiorgetti]

@lynnemorrison if the returned error is a *net.OpError, then I would suggest displaying a friendly message, something like what you had above:

Unable to communicate with the Container Engine.
Run: "skupper system install" to prepare the local environment and start the controller.

Error: <the actual error message>

This way users will, at least, have an idea on what to check.
And the error will explain the details on what is going on.

@pwright @c-kruse thoughts or suggestions?