Specify moduleMetaData in webpack per entry point

[frankandrobot]

• our use case is a legacy monorepo where every page is a micro front end
• However, all pages share a common webpack configuration---each page has its own entry page.
• as per https://docs.sentry.io/platforms/javascript/guides/nextjs/configuration/micro-frontend-support/#combining-modulemetadata-and-makemultiplexedtransport, we need to use the sentryWebpackPlugin to inject the project DSN via moduleMetaData.
• But for our case, every entry point will have it's own DSN, so we need to be able to do something like this:

module.exports = {
  plugins: [
    sentryWebpackPlugin({
      /* Other plugin config */
      _experiments: {
          moduleMetadata: ({ release, entry }) => ({ dsn: lookupDsnByEntry(entry), release })
      },
    }),
  ],
};

• alternatively, we just need a way to specify the DSN per page (bundle).