Use containers for github component testing

[jedwards4b]

We have a number of repositories in escomp, esmci, and ncar which need to start with builds of supporting software like
netcdf, pnetcdf, hdf5, mpi - it is very time consuming to build all of these packages each time for each repo. I have been reading about how to use docker images in github actions and I believe that the images from this repo could be very useful in accomplishing that end. Following this article we can build the image and cache it for reuse. This should save considerable time in testing for a number of repos. I'm going to start with https://github.com/NCAR/ParallelIO and try to run testing in the base/centos8 container found here. If/when that proof of concept works I will want to add more Dockerfiles with different mpi layers and with different versions of the libraries.

[jedwards4b]

First attempt to use this container results in an error:

#6 0.921 Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

A web search suggests that this image is out of date?
https://haydenjames.io/fix-error-failed-to-download-metadata-for-repo-appstream-centos-8/