refactor: dockerized wheel build + fast-build script, quick Mordred test, remove in-repo RDKit port

[ryan-gdm]

Makes the project easier to build and test, and cleans up old/native code paths that we’re not shipping:

1. Adds a Docker build for quick and easy wheel builds.
2. Adds a quick Python parity test to compare our descriptors with another Mordred implementation.
3. Removes the RDKit C++ port from this repo (already have an upstream branch for that work).