DFs: Add CentOS8 Stream Dockerfile

[Willsparker]

Ref; (possible Fixes): #2478

Just a quick PR to cp the CentOS7 Dockerfile, and then change the FROM argument to centos:stream8.
I sort of assume the ENV variables need to be updated too?

Checklist

• commit message has one of the standard prefixes
• faq.md updated if appropriate
• other documentation is changed or added (if applicable)
• playbook changes run through VPC or QPC (if you have access)
• for inventory.yml changes, bastillion/nagios/jenkins updated accordingly

[sxa]

I'm not sure why we need a build dockerfile here. The related issue was for a test image in the DockerStatic set. Also I don't believe centos8:stream is in the default dockerhub repo.

[Willsparker]

Ah yes, my bad. Closing PR