Move lobby presets and rewards onto the particle slot model

Team- and user-specific particles become presets built from entries,
tournament and egg hunt particles become fixed reward designs, and the
old particle enums, ParticleEnum and ParticleData are removed. The
particle menu temporarily lists only unlocked presets.

LobbySystem/src/de/steamwar/lobby/particle/elements/Circle.java

@@ -47,11 +47,6 @@ public class Circle extends DelegatingParticleElement {
         this.phase = Math.toRadians(phaseDegrees);
     }
 
-    @Override
-    public String attribute() {
-        return "PARTICLE_ATTRIBUTE_CIRCLE";
-    }
-
     @Override
     public void tick(ParticleTickData particleTickData) {
         Location location = particleTickData.getLocation();