rings: tool similar to cleanup_rings, but to make ring changes in stagings

[jberry-suse]

Seems like the regular ring changes should be fairly straight forward to automate. Look for un-resolvable packages and see if they there exists a package already in the project (or potentially in open requests) that would provide what is needed and move it to the same ring.

Could be a manual tool like cleanup or automated if either documents changes or easy to tell.

[jberry-suse]

The plan:

• project_status() to look for un-resolvable packages (perhaps filter to those related to open requests)
• check source project fileinfo_ext to see what packages provide its requirements
  • likely makes sense to fallback to primary project and that way if packages are added to rings, followup can add their requirements (and/or check specifically)
  • also possible to fallback to devel project
  • lastly another candidate for primary.gz as it would provide overview of what is already provided which short of a new request providing a new thing, but needing to move rings (corner case) should pickup the rest
• use _builddepinfo to map the packages back to source packages
• check project for those packages and if exists link them into the highest required ring

If this works well, I think it would be a candidate for adding to staging-bot, but would be another nice thing that would be neat to either have staging-bot write on diary or somewhere to easily see that it has done something. This should be seen with check and such so not a requirement.

[jberry-suse]

For SLE updates where builds are disabled looking in factory/devel or primary.gz will be the only way.

[jberry-suse]

Likely also makes sense to allow cleanup_rings to be applied to stagings that way if a request is rejected, but ring modifications were made on its behalf they can easily be undone.