Improve skill costs mechanics

[NeumimTo]

curretly spells can use either player's health or mana. I should refactor the system so it will be more flexible. by default introduce those types

• Mana (regenerated by a scheduler as currently implemented
• Health (regenerated by minecraft internal system)
• WoW warrior rage/gw2 adrenaline (you start on 0, player has to use other spells first, or attack attack enemies, its value decays over time)
• Stamina (=minecraft hunger system)

[NeumimTo]

steal this idea https://www.youtube.com/watch?v=SbdLNsWn7aI for hud will work only on 15.2+