Add jira notifications via a new WebHook in Rocket.Chat

This repository only contains a single rocket chat integration script. Go there https://rocket.chat/docs/administrator-guides/integrations/jira for more info about using it.

I don't use Jira nor RocketChat anymore, but still maintain this repository by accepting tested PR from contributors. If you are an active user of this script and want to take over you're welcome as I have very not much time for this project, and can't test the script on my side. Don't hesitate to contact me or to comment on the related issue #11