Applayout migration was not part of this, but I started with it for another ticket and then needed to change order of tickets. It didn't include any code changes so I decided to keep it.
Made external link a bit more compliant to internal links, and link buttons more compliant to regular links
Splitted ButtonProps and LinkProps in a more clear way
Moved props into the components that should always be the same, like an external link button should always looks the same.
Had to add wrapper MemoryRouter to Link buttons in stories, since they're acting as links