Provide a public API to set the environment to a given path

[brettcannon]

Discussed in #16504

^{Originally posted by brettcannon June 16, 2021}
I have an extension that currently changes the python executable being used by setting it in the user or workspace settings.json (depending how the user chooses to do it).

In the description of https://github.com/microsoft/vscode-python/wiki/AB-Experiments#deprecatepythonpath, I can't really see any way for an extension to update the python used by the vscode-python extension after the move to stop using the settings.json.

So, this is a request to provide an API/command to provide parity with what was already available prior to this change (or if there is already a way to do it, document it in https://github.com/microsoft/vscode-python/wiki/AB-Experiments#deprecatepythonpath).

Originally posted by @fabioz in a discussion

[brettcannon]

Thanks for the feature request! We are going to give the community 60 days from when this issue was created to provide 5 👍 upvotes on the opening comment to gauge general interest in this idea. If there's enough upvotes then we will consider this feature request in our future planning. If there's unfortunately not enough upvotes then we will close this issue.

[brettcannon]

Thank you to everyone who upvoted this issue! Since the community showed interest in this feature request we will leave this issue open as something to consider implementing at some point in the future.

We do encourage people to continue 👍 this issue as it helps us prioritize our work based on what the community seems to want the most.