Make getFlipperLib generally available, and use it to decouple opening links from Electron

Summary:
This stack reduces our direct dependency on Electron, for example by exposing our own API to open links.

Also exposing `getFlipperLib` as API from `flipper-plugin`, so that these utility methods are available outside plugin contexts as well.

Reviewed By: timur-valiev

Differential Revision: D29661689

fbshipit-source-id: 0c0523326eeb0d9d8fbe3e03c4609327bb53596b

desktop/app/src/devices/BaseDevice.tsx

@@ -16,7 +16,7 @@ import {
   DeviceLogListener,
   Idler,
   createState,
-  _getFlipperLibImplementation,
+  getFlipperLib,
 } from 'flipper-plugin';
 import {PluginDefinition, DevicePluginMap} from '../plugin';
 import {DeviceSpec, OS as PluginOS, PluginDetails} from 'flipper-plugin-lib';
@@ -245,7 +245,7 @@ export default class BaseDevice {
       this.sandyPluginStates.set(
         plugin.id,
         new _SandyDevicePluginInstance(
-          _getFlipperLibImplementation(),
+          getFlipperLib(),
           plugin,
           this,
           // break circular dep, one of those days again...