ESC: Importing Environments guide has obsolete screenshots

[jkodroff]

https://www.pulumi.com/docs/esc/guides/importing-environments/ has obsolete screenshots from the older version of the editor.

The screenshots should be removed in favor of simple text instructions which are more likely to stay current.

The table editor is being removed from Pulumi Cloud altogether and should be removed from the guide.

There's also no reason for us to have the two dev/prod URLs in a screenshot - they should be in plain text as well.