Add optional workaround for >Y128 Nether building (#615)

* Add optional workaround for >Y128 Nether building

This commit adds a config option for building above the Nether by changing the Nether's dimension ID to match the End's.

* Only check for workaround application once

* Fix mappings?

* Include a bit more for the above bedrock nether building config option

Co-authored-by: Redned <redned235@gmail.com>

bootstrap/velocity/src/main/java/org/geysermc/platform/velocity/GeyserVelocityConfiguration.java

@@ -76,6 +76,9 @@ public class GeyserVelocityConfiguration implements GeyserConfiguration {
     @JsonProperty("cache-chunks")
     private boolean cacheChunks;
 
+    @JsonProperty("above-bedrock-nether-building")
+    private boolean aboveBedrockNetherBuilding;
+
     private MetricsInfo metrics;
 
     private Path floodgateKey;