Remove duplicated documentation

[tau-dev]

Installation instructions for various editors are currently reproduced in slightly different forms in the README.md, the config wizard, the GitHub wiki, and the editor plugin. Failure to keep these in sync has been a cause of confusion for new users, as in #312, #295 and #222. I propose we remove the editor specific installation instructions from the README (which is currently quite intimidating), keep short instructions in the config wizard, and further details in the wiki.