Move from gulp to node scripts

[JoeRobich]

This PR moves us from Gulp to running node scripts via node run. It exposes all our tasks as entries in the packages.json scripts section. This allows us to use npm run {task} in the same manner as we were using npx gulp {task}.

Problems with gulp

• Gulp didn't release a new version for multiple years until just recently
• Gulp or one of the gulp tasks we relied on limited our ability to take newer versions of some dependencies
• Also fewer dependencies is better assuming we can do it without reimplementing our own version of gulp

Aside
I investigated using node's built-in type stripping support to replace our use of ts-node, but it required changes inside the /src directory which I was trying to avoid. At some point I am sure we can move all our code to be compatible in order to avoid the compilation step. In particular the changes required meant <type> casts became as type, enum types became const lookups, and imports of Typescript type definitions were changed to import type.

[JoeRobich]

Since CJS doesn't support top-level await we need a little wrapper function so our async tasks can run.