Create an option to archive/unarchive Groups

Problem

There is an ability to archive a project within a group, but there is no ability to archive an entire group with GitLab today.

If a product is mothballed, the operations team would like to archive the GitLab Group (& projects) so that it no longer appears within the GitLab UI like an active product that is under development.

Proposal

Add an option to "Archive group" to the "Edit Group" screen in GitLab.

1. To archive a group, locate a group, click on Edit and select Archive group. Messaging should follow a similar message as used when archiving projects:
2. Archived groups display a message on the group overview page similar as is displayed for projects: Subgroups and projects of the archived group should display this message as well.
3. To unarchive a group, locate the group, click on Edit and select Unarchive group. Messaging should follow a similar messages as used when unarchiving projects:
4. When archived, a group and its contents will be shown in the Inactive tab in Group listings (e.g. Group overview page, Your Work, Explore). Reference: design vision for Explore and Your Work.
5. When archived, a group and its contents can be unarchived by a group Owner or admin by locating the group, clicking Edit and selecting Unarchive
6. When archiving a group, all of its subgroups and projects get archived as well
   • A subgroup of an archived group cannot be unarchived. The archived group needs to be unarchived in its entirety.
   • An archived group cannot be transferred.
7. When archived, groups show the Archived badge in lists
   • All subgroups and projects of the group display the Archived badge in lists as well
8. When archived, issue status remains unchanged. Open issues remain open, and closed issues remain closed.
9. When archived, groups cannot be transferred.

Designs

See #472805 (closed).

In groups/projects settings > general> advanced add/modify the archive setting as follows:

• Add option archive group
• Add option to unarchive group
• Modify option to unarchive projects that are children of archived groups
• Modify option to unarchive groups that are children of archived groups

In groups/projects that are archived or children of archived groups add/modify a non-dismisable alert on all pages as follows:

• Add alert to groups that archived
• Add alert to projects that are children of archived groups
• Modify archived projects that were archived and are now children of archived groups
• Add alert to groups that are children of archived groups

Add/Modify tabs to the following pages to account for active and inactive groups

• Your work groups
• Modify Group overview (homepage) Inactive tab to include groups and projects

Requirements

See #382051 (closed).