Introduce DevicePlugin APIs

Summary:
This stack introduces Sandy device plugins, they are quite similar to normal plugins, but, a devicePlugin module is organized as

```
export function supportsDevice(device): boolean

export function devicePlugin(devicePluginClient)

export function Component
```

Device plugins get access to the device meta data and can subscribe to the `onLogEntry` callback and `onDestroy` lifecycle.

They will be able to store state just as normal plugins, but can't send or receive methods, so devicePluginClient is a bit limited.

This diff only sets up most of the new data structures, and makes sure everything still compiles and no existing tests fail.

To prevent this diff from becoming to big, actually loading, rendering and testing device plugins will be done in next diffs

Please take a critical look at the api proposed and the (especially) the public names used :)

Reviewed By: passy, nikoant

Differential Revision: D22691351

fbshipit-source-id: bdbbd7f86d14b646fc9a693ad19f33583a76f26d

desktop/app/src/index.tsx

@@ -44,11 +44,7 @@ export {getPluginKey, getPersistedState} from './utils/pluginUtils';
 export {Idler} from './utils/Idler';
 export {Store, MiddlewareAPI, State as ReduxState} from './reducers/index';
 export {default as BaseDevice} from './devices/BaseDevice';
-export {
-  DeviceLogListener,
-  DeviceLogEntry,
-  LogLevel,
-} from './devices/BaseDevice';
+export {DeviceLogEntry, LogLevel, DeviceLogListener} from 'flipper-plugin';
 export {shouldParseAndroidLog} from './utils/crashReporterUtility';
 export {default as isProduction} from './utils/isProduction';
 export {createTablePlugin} from './createTablePlugin';