Make package easier to compile for web-extensions

[christian-bromann]

Currently the package always requires streamroller and the RollingFileTransport which uses fs-extra as dependency. This is less ideal when bundling an extension for the web. I would suggest to either document how to set up a bundler to allow strip out these dependencies or make it so that they won't be included by tree shaking.

My current Webpack setup for this is:

webpack.config.ts#L87-L91

    alias: {
      ...stdLibBrowser,
      streamroller: false,
      './transports/rolling-file': false
    },

And to ensure that no RollingFileTransport is used I do this:

logger.ts#L26-L30

      level: this.logLevel, // See LogLevel type in @vscode-logging/types for possible logLevels
      ...(IS_WEB_BUNDLE
        ? {}
        : { logPath: context.logUri.fsPath }
      ),