text: Title: Addition: SimplifiedRegressionDashbaord
  Body: The default dashboard can be very overwhelming with lots of tabs, toggles and dropdowns. It would be nice to offer a simplified version. This can be built as a custom ExplainerComponent and included in custom, so that you could e.g.:
  
  ```
  from explainerdashboard import RegressionExplainer, ExplainerDashboard
  from explainerdashboard.custom import SimplifiedRegressionDashboard
  
  explainer = RegressionExplainer(model, X, y)
  ExplainerDashboard(explainer, SimplifiedRegressionDashboard).run()
  ```
  It should probably include at least:
  
  predicted vs actual plot 
  Shap importances
  Shap dependence
  Shap contributions graph
  
  And ideally would add in some dash_bootstrap_components sugar to make it look extra nice, plus perhaps some extra information on how to interpret the various graphs.