(feat) add port and host option to build.config

BREAKING CHANGE
Add host and port option to build.config.js. Browser Sync uses these
options. E2E tests also use these options.

How to update project to use this generator
1. Add port and host to build.config.js.
2. Update gulp broswerSync task to use host and port and open external
3. Update existing e2e tests to use browser.driver.get to use host and
port
4. npm install findup-sync