Github actions package system needs to support existing docker build scripts

[amzn-changml]

Some of the existing package build scripts being called by pull_and_build_from_git.py include Docker build and execute commands, which cause a nested docker scenario with the existing qemu docker used by the imported action uraimo/run-on-arch-action

We'll need to detect the presence of a Dockerfile in the packaged directory, then utilize that for the aarch64 build by starting up qemu, then using the standard build command. Eventually, if Github Actions is able to use a native aarch64 node, then this will become unnecessary.