Create Service Account Management Page

This issue covers creating the service account management page.

Implementation Details:

• Add table of service accounts
• Make sure table renders empty state
• Table must render for top-level group and instance level versions of the vue app.
• Vue App needs to be context aware to know which version of the REST URL to hit. We can provide URL path as injected HTML5 data attributes.
• Implement row dropdown. (Dropdown items should be stubbed out as placeholders in this issue, NO-OP if you click on them)
• Unit tests
• Adding service account button and flow is a follow-up issue.