Make sections collapsible.

It is difficult to look for target service on sites with many services and many sections. 

With this patch, you can fold sections (and expand sections) on service by clicking `+` beside service name.
Folding / expanding all sections at the same time is also available.

http://gyazo.com/15e98c01ea617292a702c94aac9eb8ce
![Preview](http://gyazo.com/15e98c01ea617292a702c94aac9eb8ce.png)