Categories overview page

[flip111]

1. Purpose
   It's not necessarily bad that this page is here. But IMO it's not a very important page. I'm sure there will be more important pages that deserve the number 2 spot in the navigation up top. I'm not saying this page is useless, but i think it's not that useful either.

What i like to see here is how Rust does it with the "are we X yet" websites. Example https://www.arewewebyet.org/ Overview of websites https://wiki.mozilla.org/Areweyet

One has to ask with what purpose the user lands on the categories page. Some use cases:

• The "wow effect", user lands on page sees that haskell has a lot of stuff and that is the goal of the page.
• The "lazy sunday afternoon" where somebody just enjoys browing to see what is out there.
• The "I'm looking for a solution to a specific technical problem". I kind of see the categories page working, though i seldomly use this page on hackage for that. Usually i either google (and land on blogs or stackoverflow) or i ask around in IRC.

Just wanted to mix in a positive point (not something to change). I think the page looks nice and clean and has good descriptions

Behind the title i would put in parenthesis the amount of packages in that category "Algorithms (139)". It's ok if users don't get always right what the 139 means, they will figure it out and it would stop them on clicking on the categories if they were planning to do that anyway.