Add CI build for RHEL8 environment

[thomas-bc]

Related Issue(s)	#3548
Has Unit Tests (y/n)
Documentation Included (y/n)

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Change Description

Fix #3548

Also standardizes a little more CI job names so they're nicely sorted

Rationale

RHEL8 compilers seem to catch more warnings than our current CI suite. Some F Prime users use RHEL8, so it's good to test on that.

[thomas-bc]

Confirmed that this set up would have caught a warning like the one fixed in #3493

[thomas-bc]

BufferLogger UTs seem to fail in a docker container. I was able to reproduce in a rhel8 container. But running on native rhel8 passed ok. I wonder if the UTs (or component itself) has something that doesn't play nice with being in a container... wil investigate

[thomas-bc]

So, for posterity ....

The issue had to do with filesystem permissions within a container. What's really weird is that the issue only appeared when running the RHEL8 container on a linux host. The same container on a macOS host would behave as expected.

Basically, chmod -w dir would not successfully remove permissions of the root user to create files in dir. The fix is to use a non-root user to run UTs. Which arguably is the way to do CI anyways, but the only official RedHat images I've found do not include a non-root end user. So I've added the creation of the user in the job itself.

[LeStarch]

LGTM