Support API keys for authenticating users as service accounts

[solocommand]

User Service

• Add an API key field to the user schema
• Add an action for updating a user with a newly generated API key (UUID + ENV var hash)

GraphQL Service

• Add mutation for calling user.regenerateApiKey on the currently logged in user
• Add a serviceAccountLogin mutation to generate a short-lived token, provided a valid API key

Management

• Add a readonly/copyable field to display the user's current API key.
• Add a refresh confirmable button to (re-)generate an API key