Allow config automatic config import from url/file

[NicoVIII]

To allow deeper integration scenarios it should be possible to define an url or a file from which the extension automatically fetch the used config in a configurable interval.

This should allow the creation of workflows to support changing the settings of a screen without connecting to it.

This option should be disabled by default of course.
There has to be a differentiation between this setting and importable ones. For security reasons it should not be possible to import this autoimport setting.