Character leveling system

Our Viking gets the opportunity to upgrade in three areas: endurance - increases maximum health; strength - increases the force of blows; luck - increases the chance of a crit (yes, crits have appeared). The code base for leveling up has been written, all that remains is to screw in the visual part. You can pump up your stats in the lab by collecting a certain number of items, from which Ada will make a potion. Items will need to be collected at a special level, this is optional, but leveling up will not hurt, because stronger mobs will be encountered.

In the future I also plan to make shooting mobs, but this is not in the next update.

For now, I will continue working on the story after the victory over the Sultan.