Ability and level improvements

[noah1510]

At the moment the level system and the ability indicators are kind of rough.
They mostly work but there a a lot of small bugs.

• fix the level ups to always reward the stats and ability points
• sync the ability points and exp properly across the server and client
• make sure the level up stuff is run on the server
• handle the ability UI better:
  • only recreate the UI parts that actually need it
  • display mana/resource cost
  • add animations for the upgrade indicator
  • display the current cooldown or remaining activation time
  • improve the tooltips and make sure they are updated properly