[DEV] Create a release pipeline for the docker-compose files needed to run a HPC cluster

[alexlovelltroy]

Our readme instructions in the subdirectory of the repo are good, but we can make it easier for new users by creating a release of just the essential files and scripts for getting started.

This task may be marked complete when we have added :

• [ ] a github action workflow to create a tarball of only the files essential for a default installation of OpenCHAMI through docker-compose
• [ ] automation for signing the tarball and generating a Github release with changelog(s)
• [ ] Instructions in the readme for downloading the most current release and verifying the signature

[synackd]

This can probably be moved from the SI project if it is still desired, since this year's SI has concluded.