View storage space consumed at a group level
Description
We should make it easy for administrators and group owners to view the storage space consumed by a specific Group. For groups with subgroups, we should also try to make it clear how the nested groups are also consuming resources, to avoid having to make administrators click through to each subgroup.
Proposal
When a system administrator, group owner, or parent group owner views a particular group, they should be able to see the usage of that group. This usage should include storage, shared CI build minutes, and other consumable resources.
A great way to visualize this data is with a Sunburst Chart. An interactive demo of one can be seen here, albeit without labels or breadcrumbs: https://bl.ocks.org/mbostock/4348373. A screenshot is below.

For the chart:
- Mouse over should update a legend with details on that group/project
- Click should "zoom" to that item, leaving a breadcrumb for knowing you are and navigating back
- Double click could open that group/project in existing (or new) window
- If a storage limit has been defined, display free space as a blank section of that size in that specific group.
This allows a great way to visualize nested relationships, while retaining the ability to browse around. The nesting should be:

We should show a summary of the total storage used by type, for all child groups/projects.
Links / references
Documentation blurb
(Write the start of the documentation of this feature here, include:
- Why should someone use it; what's the underlying problem.
- What is the solution.
- How does someone use this
During implementation, this can then be copied and used as a starter for the documentation.)