Refactor GUIs to use param's own default value

This removes the need to pass a lot of these `ParamSetter`s and
`GuiContext`s around. We also don't need explicit events to reset a
parameter anymore since you can get this information from the parameter
itself.

plugins/crisp/src/editor.rs

@@ -85,13 +85,9 @@ impl IcedEditor for CrispEditor {
     }
 
     fn view(&mut self) -> Element<'_, Self::Message> {
-        GenericUi::new(
-            &mut self.generic_ui_state,
-            self.params.as_ref(),
-            self.context.as_ref(),
-        )
-        .pad_scrollbar()
-        .map(Message::ParamUpdate)
+        GenericUi::new(&mut self.generic_ui_state, self.params.as_ref())
+            .pad_scrollbar()
+            .map(Message::ParamUpdate)
     }
 
     fn background_color(&self) -> nih_plug_iced::Color {