RPMs only target CentOS 7

[zrhoffman]

I'm submitting a ...

• new feature / enhancement request

Traffic Control components affected ...

• Grove
• Traffic Monitor
• Traffic Ops
• Traffic Ops ORT
• Traffic Portal
• Traffic Router
• Traffic Stats

Current behavior:

Right now, all of our RPMs are targeted at CentOS 7, whose Full Updates support ends in Q4 2020.

New behavior:

We should support CentOS 8 as a build target, as using CentOS 8 instead of CentOS 7 is inevitable.

Minimal reproduction of the problem with instructions:

1. Build the Apache Traffic Control RPMs
2. Notice that their filenames all end with .el7.x86_64.rpm or .el7.src.rpm