[1.16] Make it run (#3626)

* She compiles!

Also readded the armorstand ticking patch, thanks cat

* Update mob goal api

* Misc fixes to make it run

drop per playing mob spawns for now

Spigot-Server-Patches/Generator-Settings.patch

@@ -9,8 +9,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 @@ -0,0 +0,0 @@ public class PaperWorldConfig {
-     private void perPlayerMobSpawns() {
-         perPlayerMobSpawns = getBoolean("per-player-mob-spawns", false);
+             }
+         }
      }
 +
 +    public boolean generateFlatBedrock;