https://pagure.io/releng/issue/12587

G'day, for https://fedoraproject.org/wiki/Changes/KojiLocalImageBuilder I'd like the following:

• `image-builder`, and `distribution-gpg-keys` in an `image-builder-build` group (I don't know the exact name of this type of group, it's what's used by the buildroots).

This would be a new group that will get used by the new task types that will be added to the already existing `koji-osbuild` plugin but I'll make a separate releng issues for rights on those tasks after I've submitted the updates for the plugin to Fedora.

The above mimicks the koji comp group setup for `kiwi` (which has its `kiwi-build`) group. I'm trying to keep everything the same as possible with the way the `kiwi` plugin works.