GitHub scope CTA global banner

Created by: artemruts

Description

These changes add a global dismissible banner for user that is:

• on .com
• enrolled in private code
• is missing "private" scope for GitHub

Screenshot

Questions

1. When we display a global banner do we want to hide a similar alert on the "code host connections" page?
2. We'll make requests for grantedScopes only if the user does a full page refresh (unmount the top level app), when user navigates between routes we don't make additional requests. Is it ok?
3. Doesn't this grantedScopes resolver code mean we'll show a global alert and an update button for GitHub code host if we can't resolve the scope or had and error?