[navigation-next] Add landing pages for system nav group

[SuZhou-Joe]

Is your feature request related to a problem? Please describe.

As we are introducing nav group in new left navigation, and each nav group should have a landing page.

Describe the solution you'd like

Implement 2 landing pages for that.

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

#7027