Revamp information bar on Studio

In Studio, the cookie information bar:

• breaks the UI, forcing people to scroll to see the version control bar for instance as long as it's not closed + the window has been refreshed.
• is not visible enough, people don't feel like they need to close it. This prevents us from getting analytics if they agree to it.

=> Cookie information bar should be floating over the content, or use another mechanism that doesn't break the UI and provides more visibility.

Message:
This website uses cookies according to our [cookie policy]. [Agree] or [Change your settings]
Cookie policy and change your settings => sends to cookie policy
agree => closes popup and considers user is informed
closing popup => considers user is informed