RPM repository sync workflow

[himdel]

(from https://hackmd.io/Dp-kVIjnTVeQVse2w2eC-w)

• RPM repository sync workflow:
  1. Create an RPM Remote with a URL for a repository available on the internet (e.g. https://fixtures.pulpproject.org/rpm-signed/). Remotes contain all the information needed to connect to a remote repository, e.g. url, username, password
  2. Create an RPM Repository in Pulp to house mirrored content. Specify the RPM Remote from step 1 when creating the repository. Also set autopublish to True.
  3. Create a Distribution. Distributions tell the content app at which URL to serve repository content. Specify the RPM Repository from step 2 when creating the distribution.
  4. Use the Repository's sync API to create a new Repository Version by performing a sync from the Remote associated with it. This operation downloads all the packages and creates a new Repository Version.

(TODO: is this different from #85?)