Add all Thruk themes available

With the new GUI option, one cannot modify thruk themes directly.

Please add all the thruk themes. Sipmply create folders in `/srv/eyesofnetwork/eonweb/themes/` with the same name as Thruk:

```
Exfoliation
Neat
Nuvola
Thruk
Thruk2
Vautour
Wakizashi
```