Device plugin management (2/n): enable/disable, install/uninstall

Summary:
*Stack summary*: this stack adds ability to manage device plugins in the same way as client plugins: install, update, uninstall, enable (star) and disable (unstar) them.

*Diff summary*: implemented all plugin management actions for device plugins.

Changelog: it is now possible to enable/disable and install/uninstall device plugins

Reviewed By: mweststrate

Differential Revision: D26337377

fbshipit-source-id: 7d1ed61a8dc5f3339e5e548c613b67bca0c27f4f

desktop/app/src/devices/BaseDevice.tsx

@@ -248,7 +248,10 @@ export default class BaseDevice {
       instance.destroy();
       this.sandyPluginStates.delete(pluginId);
     }
-    this.devicePlugins.splice(this.devicePlugins.indexOf(pluginId), 1);
+    const index = this.devicePlugins.indexOf(pluginId);
+    if (index >= 0) {
+      this.devicePlugins.splice(index, 1);
+    }
   }
 
   disconnect() {