Log/Old build cleanup

[bdrewery]

I thought there was an issue for this but cannot find it.

We need a configurable way to cleanup old logs and builds.

[nakal]

I'd like to have this feature, too. What is the workaround for now?

[bdrewery]

It's coming in the next poudriere-devel.

I still need to add a buildclean command or something to remove old package sets.

[grahamperrin]

Also #278