If the default, instance-wide visibility were set to internal but a
group were private, the radio button would be set on internal even
though that setting were not allowed. We now consider the allowed
visibility setting for the group in determining what the default should
be.
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/62298
This removes the `ForkedProjectLink` model that has been replaced by
the `ForkNetworkMember` and `ForkNetwork` combination. All existing
relations have been adjusted to use these new models.
The `forked_project_link` table has been dropped.
The "Forks" count on the admin dashboard has been updated to count all
`ForkNetworkMember` rows and deduct the number of `ForkNetwork`
rows. This is because now the "root-project" of a fork network also
has a `ForkNetworkMember` row. This count could become inaccurate when
the root of a fork network is deleted.
