Add configurable particle slot model

Introduce parameters, particle types, designs and entries that build the
existing particle elements, store each of the 7 particle slots in its own
UserConfig key, and let LobbyPlayer select a slot next to the old enum
particles. Slots 4-5 need a team, 6-7 the server team.

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

@@ -28,6 +28,7 @@ public class Circle extends DelegatingParticleElement {
 
     private double distance;
     private double speed;
+    private double phase;
 
     public Circle(ParticleElement particleElement) {
         super(particleElement);
@@ -41,6 +42,11 @@ public class Circle extends DelegatingParticleElement {
         this.speed = speed;
     }
 
+    public Circle(ParticleElement particleElement, double distance, double speed, double phaseDegrees) {
+        this(particleElement, distance, speed);
+        this.phase = Math.toRadians(phaseDegrees);
+    }
+
     @Override
     public String attribute() {
         return "PARTICLE_ATTRIBUTE_CIRCLE";
@@ -51,7 +57,7 @@ public class Circle extends DelegatingParticleElement {
         Location location = particleTickData.getLocation();
 
         Vector vector = new Vector(distance, 0, 0);
-        vector.rotateAroundY((particleTickData.getDeg() * speed) % 360);
+        vector.rotateAroundY((particleTickData.getDeg() * speed) % 360 + phase);
         ParticleTickData nParticleTickData = particleTickData.withLocation(location.clone().add(vector));
         particleElement.tick(nParticleTickData);
     }