Most of the time forks are used for contributing code only, so not
having
issues, projects, release and packages is a better default for such
cases.
They can still be enabled in the settings.
A new option `DEFAULT_FORK_REPO_UNITS` is added to configure the default
units on forks.
Also add missing `repo.packages` unit to documentation.
code by: @brechtvl
## ⚠️ BREAKING ⚠️
When forking a repository, the fork will now have issues, projects,
releases, packages and wiki disabled. These can be enabled in the
repository settings afterwards. To change back to the previous default
behavior, configure `DEFAULT_FORK_REPO_UNITS` to be the same value as
`DEFAULT_REPO_UNITS`.
Co-authored-by: Brecht Van Lommel <brecht@blender.org>
2741546bed