Show keywords with the most crates on the front page (and categories too when they're done)

[carols10cents]

I really like how Package Control has "labels" (their version of keywords) on their front page, alongside similar things to what crates.io has on its homepage:

I don't think /keywords is linked anywhere prominent right now, so it's hard to even know what keywords people are using on their crates unless you know to type in that URL :) This would help make keywords more visible and useful.