Add optic api documentation

[ukmadlz]

trafficstars

This boilerplate starter for a TS based Express app is fantastic, I really like how it lays out the OAuth flow as well as all the basic user endpoints to extend off.

I thought it'd be great to add something to assist with documenting APIs build off it. I've added Optic as a way to automate the collection of API endpoint documentation, I've gone ahead and added the middleware and the pointers in the README. I've set it to only run in non-production setups with minimal hassle and to not get in the way of the users flow if they don't want to use the CLI.

[microsoft-cla-retired[bot]]

All CLA requirements met.