Common components for the dashboard

I would have loved to clean this up better, but for now there is just no time... and I want you guys to use it.

Included:

* Brand new side bar! Only one real level so far, second "faked" level possible for demo. (More below)
* Rejuvenated navigation bar. (Changes according to current wrapper, new search bar)
* Better wrapping of the different routes with regards to their purpose, but also in general.

Things I would have liked to do:

* Start to organize LESS a little, perhaps in some sub-files, I have an idea for the organization.
* Create a Router-ready component for the navigation bar drop-down menus like we did for the single menu items.
* Proper sidebar item nesting and collapsing.
* Investigate an input add-on button workaround or implement the functionality.
* Tinker the structure and disposition of the potential sidebar buttons properly.
Isn't it the whole point of having our own navigation bar component? It doesn't bring new features, it just wraps React-Bootstrap's `NavBar` with some knowledge proper to our project. I agree however that if we had yet another "version" for the website which used the navigation bar with other variations, we could start looking into other approaches.