Integrate the new cloud plugin in the webUI

The preferred way of wrapping long lines is by using Python's implied
line continuation inside parentheses.

Fix wrong indentation too.

On Windows, fallback to %APPDATA% if %LOCALAPPDATA% doesn't exist.

Global name standalone not defined (#1030). Correct only the error message at the end of Glances but not the main cause of the issue (Webserver interface is not displayed)