Webhooks: use winston for logging and rotate log files

labs/bbb-callback/.gitignore

labs/bbb-callback/README.md

labs/bbb-callback/application.coffee

labs/bbb-callback/callback_emitter.coffee

labs/bbb-callback/config/bbb-webhooks.logrotate

labs/bbb-callback/hook.coffee

labs/bbb-callback/id_mapping.coffee

labs/bbb-callback/log/.gitkeep

labs/bbb-callback/logger.coffee

labs/bbb-callback/package.json

labs/bbb-callback/web_hooks.coffee

labs/bbb-callback/web_server.coffee