build: Add include_fabric and include_forge property

Author: BlayTheNinth

gradle.properties

@@ -45,4 +45,7 @@ cloth_config_version=9.0.94
 # Gradle
 org.gradle.jvmargs=-Xmx3G
 org.gradle.daemon=false
+
+include_forge=true
+include_fabric=true
 org.gradle.parallel=false

settings.gradle

@@ -12,4 +12,10 @@ pluginManagement {
     }
 }
 
-include("common", "fabric", "forge")
+include("common")
+if (include_fabric) {
+    include("fabric")
+}
+if (include_forge) {
+    include("forge")
+}