We already know how the bundle is called, what the channel should be, etc.
Therefore, we can already open PR adding 4.8 channel and 4.8.0 bundle (placed in both 4.8 channel and stable channel).
When 4.8.0 release time comes, this PR will already be there and can be merged (after potentially resolving conflicts).

This PR should be referenced as an example for Y-Streams in the release procedure.

Update the release procedure https://spaces.redhat.com/display/StackRox/Managing+a+Downstream+RHACS+Release+on+Red+Hat+Infrastructure with steps for FBC release for new Y-Stream. (This assumes we have FBC part of the release procedure already documented, as part of ROX-27031.)