Stats: Add "Skip" links

[hoverduck]

The Stats pages have lots of content divided into many modules. For someone navigating with only a keyboard, though, it's a lot of work to get to the stats you need.

So how about we add skip links on every module, effectively allowing you to tab to "Posts & Pages", and then select "Jump to Referrers"?

[stale]

This issue has been marked as stale because it hasn't been updated in a while. It will be closed in a week. If you would like it to remain open, can you please comment below and see what you can do to get things moving with this issue? Thanks! 🙏