Webhooks: local config, docs and improve how the checksum is calculated

The way the checksum is calculated now is more similar to the other API calls,
specially setConfigXML. It uses the content type 'application/x-www-form-urlencoded'
so the information in the post body doesn't have to be converted from/to
js/string, preventing possible checksum errors in different programming
languages.
Webhooks: add an extra app to print events from a meeting

Utility app to help a user find out the events that happen in a meeting.
Webhooks: add config files for upstart and monit
Webhooks: adjustments for the app when running in production
Webhooks: use winston for logging and rotate log files