Convert code to use Promises

[dmuth]

This code is many years old, and I should consider replacing seq() with promises.

For development and testing, I should create this code in a separate branch and deploy it to Heroku and let it run for awhile before merging to master.

Related reading:

• https://www.geeksforgeeks.org/using-async-await-in-node-js/
• https://blog.risingstack.com/mastering-async-await-in-nodejs/

[dmuth]

Take care of in the promises branch.