feat: add docs for symlink validation skipping (#462)

Author: mja00

docs/paper/admin/reference/system-properties.md

@@ -225,3 +225,7 @@ It also remaps plugin CB calls to remove the version information.
 
 - **default**: `false`
 - **description**: Whether the bundled spark profiler should be disabled in favor of a standalone plugin. If the spark plugin is not found, the bundled version will be loaded regardless of the setting, unless it is [explicitly disabled](/paper/reference/global-configuration#spark_enabled).
+
+#### paper.disableWorldSymlinkValidation
+- **default**: `false`
+- **description**: Disables the folder walk and symlink validation when loading a world. Significantly improves world loading speed on massive worlds (>1TB). This does not disable symlink verification of datapacks.