Onboarding - waiting for stack set up view

Proposal

This loading view should render when the user has triggered the backend stack service, and we're waiting for it to complete.

Design

Link to SVG

Implementation plan

1. After triggering the GraphQL mutation we should show this view
2. We should then wait for the mutation to return with the projects jitsu key before moving onto the next view (instrumentation details)
3. Add specs