NodeJS-compatible modules

In the previous release I thought I was switching to ES modules in a compatible way, but I didn't know exactly how NodeJS wanted it. After much experimentation and help from @sundevour, this release should be compatible with newer Nodes (13.2+), through their native ES module support.

Furthermore, there are now some extra helpers in the destiny2 module for dealing with the manifest database - downloading it (whole or in parts) and accessing typed subsets.