Add links to mistral.dev README
# FOR DEVELOPMENT PURPOSES ONLY
These configuration files are for development purposes only.
-For a proper Mistral configuration, please review StackStorm and Mistral documentation.
+For a proper Mistral configuration, please review [StackStorm](https://docs.stackstorm.com/index.html) and [Mistral](https://docs.openstack.org/mistral/latest/) documentation.
