Support build inside docker container

[chriswue]

Instead of having to install a lot of stuff on your host, it would be nice to have the build encapsulated inside a docker container. Would probably also make it easier to run in different pipelines.

This PR:

1. Adds a Makefile to kick-off the build and also to perform the actual build steps inside the container
2. Add a Dockerfile that will be used to run the build
3. Updates the README
4. Improves the Linux clone speed by performing a shallow fetch of the required SHA instead of cloning the entire repo.