Clean up QPL integration

Summary:
Removed the Flipper QPL integration, see:
https://fb.workplace.com/groups/flippersupport/permalink/1200183003795689/

It complicates our build setup significantly, without actually being used anywhere for the past year. Apparently it doesn't solve a gap compared to the scuba logging we have already in place.

Reviewed By: passy

Differential Revision: D30911573

fbshipit-source-id: 836e2aba0c92c0eed9fed0dfb12bd8bdcb8c7d71

desktop/scripts/paths.ts

@@ -8,7 +8,6 @@
  */
 
 import path from 'path';
-import isFB from './isFB';
 
 export const rootDir = path.resolve(__dirname, '..');
 export const appDir = path.join(rootDir, 'app');
@@ -23,4 +22,3 @@ export const babelTransformationsDir = path.resolve(
   'babel-transformer',
   'src',
 );
-export const jsSharedDir = isFB ? path.resolve(rootDir, '../../js-shared') : '';