Implement API keys frontend

[alexmatson-da]

Requirements:

• Add a "Service Accounts" menu item + page to the WG UI
• Display a button to generate a new key.
  • Allow the user to specify a human readable name to the key
  • After generating, the UI should show the key to the user only once and not store it anywhere.
• Display all existing SA keys
• Display a button to revoke a key
• In the Activities page, specially mark transactions that were executed by a SA