Simplify NetworkManager's request/response management
Simplify NetworkManager's request/response management

This patch:
- drops Request dependency on NetworkManager
- drops Response dependency on NetworkManager
- drops requestIds from Request and Response objects

puppeteer/puppeteer,ianchn/puppeteer,puppeteer/puppeteer,michaelfward/puppeteer,GoogleChrome/puppeteer,elisherer/puppeteer,a1ph/puppeteer,GoogleChrome/puppeteer,a1ph/puppeteer,elisherer/puppeteer,brutalcrozt/puppeteer,ianchn/puppeteer,puppeteer/puppeteer,brutalcrozt/puppeteer,GoogleChrome/puppeteer,michaelfward/puppeteer,puppeteer/puppeteer