add NodeJS-oriented Twilio config

[Van Nguyen]

There are some plugins we can possibly add tailored specifically for NodeJS applications, so it might be helpful to have a NodeJS twilio config.

Some examples:
https://github.com/nodesecurity/eslint-plugin-security
https://github.com/mysticatea/eslint-plugin-node

[Alice Cai]

we do have https://github.com/twilio-labs/twilio-style/blob/master/packages/eslint-config-twilio-base/rules/node.js, but those would be good plugins to add! @ktalebian recently added one for mocha so maybe we could consolidate that into a node config?

[Van Nguyen]

hmm since mocha is environment-agnostic, i think it might better to keep them separate, personally. but full disclosure, i don't actually know if using a node-specific eslint config for a browser-specific environment could throw any additional issues or vice versa?