Conflicting groups should handle conflicting inclusions automatically (#12005)
This adds support for inferring dependency group conflict sets from the
directly defined conflicts in configuration. For example, if you declare
a conflict between groups `alpha` and `beta` and `dev` includes `beta`,
then we will infer a conflict between `dev` and `alpha`. We will also
handle a conflict between two groups if they transitively include groups
that conflict with each other. See #11232 for more details.
Closes #11232