AngularJS-version of add prefix page

Created an AngularJS-version of the add prefix page. Links to it has been added to the prefix list (to allocate a prefix from a prefix) and the pool list (to allocate a prefix from a pool). Manual assignment is also supported, but there is no link to it so far.

It's still missing some of the flashy features such as scrolling to next relevant part of the page and animated background colors for highlighting.
Nope, that's the delay between a key has been pressed and the request is sent, unless another key is pressed. It provides the same functionality as https://github.com/SpriteLink/NIPAP/blob/master/nipap-www/nipapwww/public/nipap.js#L855. I'll add some comments to make it clear what the function is used for.

Probably much of this code can be replaced with some sort of widget. I'll add a note that we should look into that as well.