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/Optimize-Pathfinding.patch

@@ -7,7 +7,7 @@ Prevents pathfinding from spamming failures for things such as
 arrow attacks.
 
 diff --git a/src/main/java/net/minecraft/server/NavigationAbstract.java b/src/main/java/net/minecraft/server/NavigationAbstract.java
-index 62cb81516..8111317e3 100644
+index d1d16b25d0..5d6f726d05 100644
 --- a/src/main/java/net/minecraft/server/NavigationAbstract.java
 +++ b/src/main/java/net/minecraft/server/NavigationAbstract.java
 @@ -0,0 +0,0 @@ public abstract class NavigationAbstract {
@@ -20,8 +20,8 @@ index 62cb81516..8111317e3 100644
 +        }
 +
          PathEntity pathentity = this.a(entity);
- 
 -        return pathentity != null && this.a(pathentity, d0);
++
 +        if (pathentity != null && this.a(pathentity, d0)) {
 +            this.lastFailure = 0;
 +            this.pathfindFailures = 0;