Add Optimus - a Ring middleware for frontend performance optimization.

I had a hard time figuring out a category for this one.

It's not a **Web Framework**. It's not about **Web Testing** or **Web Server Abstractions**. It might be placed under **Response Middleware**, but it also cares about the request - and it wouldn't be very descriptive. I figured the **Performance** category was about backend performance. And while it does **JavaScript Minification**, that's only a small part of it.

I ended up creating a new category, even tho that feels a bit cheeky. I'm certainly open to other suggestions.

Thanks :)