web: Mark packages as private

This prevents accidental publication of packages that shouldn't
be published. Some packages were already marked as such, so it's a
bit more consistent.

web/packages/core/package.json

@@ -3,6 +3,7 @@
     "version": "0.1.0",
     "description": "Core bindings for Ruffle",
     "license": "(MIT OR Apache-2.0)",
+    "private": true,
     "main": "./pkg/index.js",
     "types": "./pkg/index.d.ts",
     "files": [

web/packages/selfhosted/package.json

@@ -3,6 +3,7 @@
     "version": "0.1.0",
     "description": "Putting Flash back on the web. Ruffle will polyfill all Flash content and replace it with the Ruffle flash player.",
     "license": "(MIT OR Apache-2.0)",
+    "private": true,
     "keywords": [
         "flash",
         "swf"