Expose API for when the list of interpreters have changed

[DonJayamanne]

Currently there's no way for Jupyter to know when user creates a new Python environment (conda, or the like).

Is it possible to get an event so we know that new interpreters have been created.

Note: Once thats done, how would we get these new interpreters. Not sure the GetInterrpeters is the best API for this, as that will return all interpreters all over again. Personally it would be nice to have something we can subscribe to, like an observable, this way we only get whats new).

[brettcannon]

There's no way for us to know when a conda environment is created outside of the local environment since there isn't a push notification from conda itself. Short of polling conda for that information I don't see how we can provide this without hacking around conda and we explicitly are trying not to do that anymore.

[DonJayamanne]

we explicitly are trying not to do that anymore

Thanks