Create swagger/openAPI doc homepage

[srkirkland]

this app has a few API endpoint available from the index.ts file. Specifically we want to focus on the following endpoints.

• POST: /initialProcessing
• POST: /process
• POST: /processDistance
• POST: /processRoutes

Take a look at https://github.com/ucdavis/fuel-reduction-cost-simulator, which has swagger UI served from the homepage (https://fuel-reduction-cost-simulator.azurewebsites.net/). LCA package is another example: https://github.com/ucdavis/LCA.

We want to do the same thing, so when I do a GET against a running version of this backend, I see the swagger docs which describe all of the parameters and models for each of the above endpoints.