Add common methods from topology controllers to new mixin
user
```ruby
module TopologyMixin
  def show
    # When navigated here without id, it means this is a general view for all providers (not for a specific provider)
    # all previous navigation should not be displayed in breadcrumbs as the user could arrive from
    # any other page in the application.
    @breadcrumbs.clear if params[:id].nil?
    drop_breadcrumb(:name => _('Topology'), :url => '')
  end

  def index
    redirect_to :action => 'show'
  end

  def data
    render :json => {:data => generate_topology(params[:id])}
  end

  private

  def set_session_data
    session[:layout] = @layout
  end
end```
assistant