stop add workspace plugins automatically to launch config

It is very annoying if every bundle I added to my workspace is also
added to the launch configuration and must be deactivated manually.
A launch configuration should represent a configuration that is changed
manually if additional bundles should be added.

If the automatically addition of plugins is deactivated, we could stop
adding plugins to deselected_workspace_plugins.

Signed-off-by: Markus Rathgeb <maggu2810@gmail.com>