[RFE] Add support for yum repos

[aleiner]

Is your feature request related to a problem? Please describe.

Describe the solution you'd like

When adding a folder structure to hauler, everything get's flattened. If you ran createrepo with the intent of creating a valid yum repository, the repodata folder won't be present. Would it be possible to allow the concept of folders to exist to preserve the ability to haul and serve yum repos?

Describe alternatives you've considered

Additional context