Switch to using ForgeFlower for Paper Only mc-dev imports

ForgeFlower is better than Spigots FernFlower at decompiling the source.

However, in order to maintain the CraftBukkit patches, we must keep
using spigots for the primary.

However, for any file that we import on top of Spigots imported files
there is nothing stopping us from using better decompiled files.

So these changes will use ForgeFlower to maintain a better set of
decomped files, so anything we add on top of Paper can start off
in a better spot.

Spigot-Server-Patches/Add-configurable-despawn-distances-for-living-entiti.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Add configurable despawn distances for living entities
 
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index de8680e4dd..02f7e506e3 100644
+index 341038fc4d..3e1f4be10f 100644
 --- 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 {
@@ -30,7 +30,7 @@ index de8680e4dd..02f7e506e3 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/EntityInsentient.java b/src/main/java/net/minecraft/server/EntityInsentient.java
-index 6e324ad589..98b28e8573 100644
+index cc74150dae..9e95ede7fe 100644
 --- a/src/main/java/net/minecraft/server/EntityInsentient.java
 +++ b/src/main/java/net/minecraft/server/EntityInsentient.java
 @@ -0,0 +0,0 @@ public abstract class EntityInsentient extends EntityLiving {