Publish flipper-server to NPM (#3224)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/3224

Automatically publish to https://www.npmjs.com/package/flipper-server

Changelog: [experimental] It is now possible to run a full fledged Flipper as node + browser appication by using `npx flipper-server`

Pull Request resolved: https://github.com/facebook/flipper/pull/3224

Test Plan:
https://github.com/facebook/flipper/runs/4659854128?check_suite_focus=true

Checked that the build is non-fb, has no fb plugins etc, and runs from npm

{F690008124}

{F690008123}

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Reviewed By: nikoant

Differential Revision: D33297125

Pulled By: mweststrate

fbshipit-source-id: b5fe6fcb81c665036273db814cb61855aaceff85

desktop/scripts/build-flipper-server-release.ts

@@ -209,6 +209,7 @@ async function modifyPackageManifest(
   const manifest = require('../flipper-server/package.json');
 
   manifest.version = versionNumber;
+  manifest.private = false; // make this package npm-publishable
   if (hgRevision != null) {
     manifest.revision = hgRevision;
   }
@@ -262,6 +263,7 @@ async function modifyPackageManifest(
   if (argv.npx) {
     // This is a hack, as npx cached very aggressively if package.version
     // didn't change
+
     console.log(`⚙️  Installing flipper-server.tgz using npx`);
     await fs.remove(path.join(homedir(), '.npm', '_npx'));
     await spawn('npx', [archive, argv.open ? '--open' : '--no-open'], {