Make the Docker image smaller and build faster

[karalekas]

• Once we downgrade quilc to use glibc 2.28, we can reduce the image size and build time
• Additionally, we can only copy over the binaries themselves (rather than the full repos)
• Could also experiment with using a .dockerignore file to get rid of the .git and docs directories, but should probably add the commit information inside the image somehow (via an ENV, file, or addition to the version like in Package and push to Test PyPI every commit #1017)