Elk service to see output and dashboard metrics

[machzqcq]

Added elk service , so that with one command docker stack..., all services, including elasticsearch, logstash come up and just import the dashboard template and we can see the value of this repo instantly. I opened issue-3, however was able to get around and hence submitting this pull request for you to evaluate and close the issue if this pull request is acceptable.

[bvis]

Hi, this contribution is highly appreciated! Thanks for your effort. ;)

Unfortunately I saw this after trying to fix your original issue and I added my own solution.

Please, check it if you have time to let me know if it's enough for you or you think this PR could be adapted to fit with the new changes.

[machzqcq]

Thank you ! In my opinion, with my PR, we add another service to the same docker-compose yml and we are good to go (leaner over creating yet another compose file). That said, I am evaluating from my context with minimal changes. It's your repo and your decision , totally up to you ;)