Provide more granularity to storage usage

Currently the option to see the storage is on a site level, and there is no way to verify if this is caused by a single project with a large number of attachments, or one single ticket, or whether it's caused by many attachments, etc.

The suggestion is to add more detail to this report so it is possible to drill down and see a list storage consumers on each product, with Jira showing it per project, and then per issue.

This allows administrators to detect when something is using more space than normal and also from using more resources on Atlassian side.