Display VRF RT and name on prefix list page

Instead of just showing the RT, and in the case of the default VRF, just
the name, we now display both the name and the RT on the prefix list
page!

Part of #386.
Revamp look of VRF RT in prefix list

The VRF RT in the prefix list now has an amazing new look that really
makes it pop out!!

Also fixed a JavaScript error on the prefix_add when it is not being
called from the pool page.

Part of #386.
Fix floating header prefix alignment

Aligns the prefix column header better with the actual prefixes.
Added a slight shadow to the VRF in prefix list

Making it pop!

Part of #386.
Revamp look of RT in VRF Selector

Got some inspiration from how the VRF thingy in the prefix list looks.

Part of #386.
Add class for blue button

Not that we need it right now, but might be usable. The search button
could use this class...
Change background of floating header

This makes sure we completely cover underlying objects.

Fixes #437.
Final version of VRF RT box colors

So, previous colors were perhaps a tad dark. Here's a new lighter
version that we believe everyone will be happy with :)

Part of #386.
Revamp VRF selection for new prefixes

The display of the destination VRF for new prefixes has been given a new
look (uniform with the VRF selector) that includes the VRF RT, name and
description.

This also means #386 is fixed as the display of VRF RT information is
now uniform.

Fixes #383.