[Fixup] Yum connection troubleshooting

### What example(s) need improvement?
https://github.com/IBM/ibmi-oss-docs/blob/master/troubleshooting/YUM.md

### What improvement(s) could be made?
Should clean it up to separate out the use case where `ibmi-repos` is not installed. In net, if IBM i repos isn't installed, get it installed! If you can't get it installed, well then talk to support or something