Align masthead with ACM

We need to coordinate with the ACM team so that the masthead looks the same when switching between contexts. This might require us to consume a common masthead component in OCP console.

The ACM team will need to honor our custom branding configuration so that the logo does not change when switching contexts.

Known differences:

• Branding customization
• Console link CRDs
• Global notifications
• Import button
• Notification drawer
• Language preferences
• Search link (ACM only)
• Web terminal (ACM only)

Open questions:

• How do we handle alerts in the notification drawer across cluster contexts?