remove setup method in plugins

Summary:
Plugins had their custom setup method which needed to be called externally. That is what consturctors are for. This removes the setup method and moves ths logic to the constructor.
The setup method was called to late which caused the graphQL plugin to crash. With the logic now being in the constructor, it is ensured that it is called at the initialization.

Reviewed By: jknoxville

Differential Revision: D8769807

fbshipit-source-id: 7b4ab4815bbe397c80998adcb89ca361df6970d3

src/PluginContainer.js

@@ -107,7 +107,6 @@ class PluginContainer extends Component<Props, State> {
     const {target} = this.state;
     if (ref && target) {
       activateMenuItems(ref);
-      ref._setup(target);
       ref._init();
       this.plugin = ref;
     }
@@ -135,6 +134,7 @@ class PluginContainer extends Component<Props, State> {
               logger: this.props.logger,
               persistedState: pluginStates[pluginKey] || {},
               setPersistedState: state => setPluginState({pluginKey, state}),
+              target,
               ref: this.refChanged,
             })}
           </ErrorBoundary>