Adds Storage Counter

What does this MR do?

Frontend

• Add a new storage tab
• Create a new Vue + Graphql App
• Fix the menu entry only being visible when there is a limit
• Update the empty text to say: = s_('UsageQuota|This namespace has no projects which use shared runners')

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Part of gitlab-org/gitlab-ce#59232