This is like the ‘pill’ pattern that we use for filtering lists of
notifications. However it is meant for navigating between discrete
things, not a filtered view of the same list.
This is why is has a gutter between each item, and no selected state.
Turns out we already had a pattern about this on the dashboard, so this
commit also changes the dashboard to use the same code.
This commit adds a placeholder page which, for now, just has links to
the API keys page and links to the clients.
There’s more stuff to come on this page, but this commit just does the
reorganising so that it’s easier to review.
