SMTP plugin

[jaylaprade]

Request to have SMTP plugin added to sensu-plugins organization

I would like to purpose the addition of this plugin to the sensu-plugins organization in hopes of better community support and exposure.

Repo to transfer:

https://gist.github.com/benlemasurier/baecbb7f666b8d750b85

[jaylaprade]

Tagging @majormoses per his request in the Slack Channel.