Warn if there are archived projects upon Group deletion
Description
Let's improve the deletion warning for groups to ensure the user is aware that group deletion will include archived projects
Proposal
When deleting a group we don't warn about the consequences for archived projects. Archived projects are excluded from project counters so it's easy to think that a group is empty if it contains archived projects but no unarchived projects.
We should update the deletion guidance for groups to display the number of projects, archived and unarchived that would be deleted as part of the operation to avoid against mistakes.
We already do something similar for user and account deletion by advertising the number of personal projects that will be also be deleted as part of the process.
This proposal was originally asking for a new column for groups to show the number of archived projects.
### Description
Add a column showing an archived project count to the group list page.
### Proposal
On the group listing page, there's no way to tell how many archived projects are in a group. It would be useful to have another column that shows a count for archived projects. For example, I have a `legacy` group that contains several archived projects that used an old bug tracking system, but I can't (easily) see how many archived projects are in the group.
Clicking through to the group page shows an empty project listing (by default - or my default settings), so, if a group contains *only* archived projects, it can give a false impression the group is empty. I think it adds to the risk of someone accidentally deleting a group that isn't empty (I almost did).
![gitlab-group-list](/uploads/36a3809b7868c6a409fa085a9f3e4f70/gitlab-group-list.png)