[Masthead] - [Add missing Masthead demos]

[tlabaj]

Is this a new component or an extension of an existing one?
What is the existing component, if any?
Masthead

Describe the feature
A clear and concise description of the new feature. What is the expected behavior?

The following task should be completed to close this issue:

• Docs: - [Masthead] - [Make the Basic demo full screen] #7210
• Masthead: add demo that includes horizontal nav #6826

[mcarrano]

It's not clear that we need some of these demos. Adding the 'needs info' tag so we can review further.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.