Create hamburger menu dropdown links

Current version uses the navbar to navigate the website.
This takes up space and limits the amount of buttons we can have without making them dropdown menus.

Proper websites uses hamburger menus which expands an overlaying menu. We should have something similar (take github.com as example). Hamburger menu should probably expand from the right, but from the top might work as well.

Create mock-ups for design layouts and once a decision has been reached regarding which solution looks the best, implement the solution.

Review the current navbar and prepare mock-ups for the proposed hamburger menu, considering an expanding menu from the right or top. The work is done when a layout has been selected and the corresponding navigation solution has been implemented.

Written by the indexing model from the issue text.