Update docs for request-api
Update docs for request-api

- Remove deprecated Request.getLogger() reference and add info to
  Request.log
- Fix link in Plugins.requestLogger

fixes #1011

hekike/node-restify,gergelyke/node-restify,restify/node-restify,myroid/node-restify,mcavage/node-restify,kusor/node-restify,myroid/node-restify,restify/node-restify