Updated unit qualities for Norsca patch.

Bug-fixing about the custom ability not appearing on the unit card

- removed regeneration
- added in return a custom ability, Blood Knight's Hunger (basically the hunger, but for a more loreful meaning, it has a slightly powerful effect)

- added more variation to the equipped sword (now they have also the grave guard sword)
- update screenshots

- the unit now have the vigour immunity
- little bump to the health (5760 hp ---> 6420hp)
- increased price and upkeep a bit in return