We currently have the following button classes: ButtonStyleButton, ContainedButton, ElevatedButton, FlatButton, MaterialButton, OutlineButton, OutlinedButton, RaisedButton, RawMaterialButton, and TextButton.

My understanding is that the best practice is to use OutlinedButton, ElevatedButton, and TextButton, and use ButtonStyleButton for custom buttons.

I propose that we deprecate OutlineButton, RaisedButton, ContainedButton, FlatButton, MaterialButton, and RawMaterialButton, each with a pointer to the relevant class, and that we update the documentation for OutlinedButton, ElevatedButton, TextButton, and ButtonStyleButton to all include sample code, and that we remove the detailed documentation from the deprecated classes to clearly indicate which are the preferred classes.