Create an app only when needed

Changes

• App is not created upon first visit, and is only created when needed

Test Plan

No auto-registering of apps upon first visit:

• Open private window
• Open devtools
• Open pleroma-fe
• Verify no request to POST /api/v1/apps is made

Auth functionalities:

• In private window and normal window, verify registration and login still works
• Refresh, verify we are still logged in, and can access authenticated APIs