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/Fix-client-rendering-skulls-from-same-user.patch

@@ -62,26 +62,17 @@ index a63a5811d6..cab8374832 100644
              }
              // CraftBukkit end
 diff --git a/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java b/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
-index 33436ac65b..6321010246 100644
+index af382815f3..22a262bb60 100644
 --- a/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
 +++ b/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
 @@ -0,0 +0,0 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
- 
+             int j = blockposition.getY() >> 4;
              if (this.f() || (i & 1 << j) != 0) {
                  NBTTagCompound nbttagcompound = tileentity.aa_();
 +                if (tileentity instanceof TileEntitySkull) { TileEntitySkull.sanitizeTileEntityUUID(nbttagcompound); } // Paper
- 
                  this.e.add(nbttagcompound);
              }
-@@ -0,0 +0,0 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
-             BiomeBase[] abiomebase = chunk.getBiomeIndex();
- 
-             for (l = 0; l < abiomebase.length; ++l) {
--                packetdataserializer.writeInt(IRegistry.BIOME.a((Object) abiomebase[l]));
-+                packetdataserializer.writeInt(IRegistry.BIOME.a(abiomebase[l])); // Paper - decompile fix
-             }
          }
- 
 diff --git a/src/main/java/net/minecraft/server/TileEntitySkull.java b/src/main/java/net/minecraft/server/TileEntitySkull.java
 index e59f3c21d7..05fca47f34 100644
 --- a/src/main/java/net/minecraft/server/TileEntitySkull.java