Create header block

[j-ferber]

Create a block for the navbar of every page. Here is our current design from Sahana:

For a reference to what should show up on hover, use the header from the current InReach site: https://inreach.org/

Here is a page of example navbars: https://ui.mantine.dev/category/headers/

I would base this header off of the header with menus from the page.

Documentation of the Menu component: https://mantine.dev/core/menu/